CHASING THE IDENTIFICATION OF ASCA GALACTIC
OBJECTS (ChIcAGO): AN X-RAY SURVEY OF
UNIDENTIFIED SOURCES IN THE GALACTIC PLANE. I.
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Citation
Anderson, Gemma E., B. M. Gaensler, David L. Kaplan, Patrick
O. Slane, Michael P. Muno, Bettina Posselt, Jaesub Hong, et al.
“ CHASING THE IDENTIFICATION OF ASCA GALACTIC
OBJECTS (ChIcAGO): AN X-RAY SURVEY OF UNIDENTIFIED
SOURCES IN THE GALACTIC PLANE. I. SOURCE SAMPLE
AND INITIAL RESULTS .” The Astrophysical Journal
Supplement Series 212, no. 1 (May 1, 2014): 13.
As Published
http://dx.doi.org/10.1088/0067-0049/212/1/13
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American Astronomical Society
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ACCEPTED TO A P J: F EBRUARY 28, 2014
Preprint typeset using LATEX style emulateapj v. 12/16/11
CHASING THE IDENTIFICATION OF ASCA GALACTIC OBJECTS (CHICAGO) - AN X-RAY SURVEY OF
UNIDENTIFIED SOURCES IN THE GALACTIC PLANE. I: SOURCE SAMPLE AND INITIAL RESULTS
G EMMA E. A NDERSON 1, † , B. M. G AENSLER 1 , DAVID L. K APLAN 2 , PATRICK O. S LANE 3 , M ICHAEL P. M UNO 4, ‡ , B ETTINA P OSSELT 5 ,
JAESUB H ONG 3 , S TEPHEN S. M URRAY 6 , DANNY T. H. S TEEGHS 7 C RYSTAL L. B ROGAN 8 , J EREMY J. D RAKE 3 , S EAN A. FARRELL 1 ,
ROBERT A. B ENJAMIN 9 , D EEPTO C HAKRABARTY 10 , JANET E. D REW 11 , J OHN P. F INLEY 12 , J ONATHAN E. G RINDLAY 3 , T. J OSEPH W.
L AZIO 13 , J ULIA C. L EE 3 , J ON C. M AUERHAN 14 , M ARTEN H. VAN K ERKWIJK 15
arXiv:1403.0404v1 [astro-ph.HE] 3 Mar 2014
ACCEPTED TO A P J: February 28, 2014
ABSTRACT
We present the Chasing the Identification of ASCA Galactic Objects (ChIcAGO) survey, which is designed
to identify the unknown X-ray sources discovered during the ASCA Galactic Plane Survey (AGPS). Little is
known about most of the AGPS sources, especially those that emit primarily in hard X-rays (2 − 10 keV) within
the Fx ∼ 10−13 to 10−11 erg cm−2 s−1 X-ray flux range. In ChIcAGO, the subarcsecond localization capabilities
of Chandra have been combined with a detailed multi-wavelength follow-up program, with the ultimate goal
of classifying the > 100 unidentified sources in the AGPS. Overall to date, 93 unidentified AGPS sources
have been observed with Chandra as part of the ChIcAGO survey. A total of 253 X-ray point sources have
been detected in these Chandra observations within 30 of the original ASCA positions. We have identified
infrared and optical counterparts to the majority of these sources, using both new observations and catalogs
from existing Galactic plane surveys. X-ray and infrared population statistics for the X-ray point sources
detected in the Chandra observations reveal that the primary populations of Galactic plane X-ray sources that
emit in the Fx ∼ 10−13 to 10−11 erg cm−2 s−1 flux range are active stellar coronae, massive stars with strong
stellar winds that are possibly in colliding-wind binaries, X-ray binaries, and magnetars. There is also a fifth
population that is still unidentified but, based on its X-ray and infrared properties, likely comprise partly of
Galactic sources and partly of active galactic nuclei.
Keywords: surveys – X-rays: general – X-rays: binaries – X-rays: galaxies – X-rays: stars
1. INTRODUCTION
1 Sydney Institute for Astronomy, School of Physics, The University of
Sydney, NSW 2006, Australia: gemma.anderson@astro.ox.ac.uk
2 Department of Physics, University of Wisconsin, Milwaukee, WI 53201,
USA
3 Harvard-Smithsonian Center for Astrophysics, Cambridge, MA 02138,
USA
4 Space Radiation Laboratory, California Institute of Technology,
Pasadena, CA 91125, USA
5 Department of Astronomy and Astrophysics, Pennsylvania State University, PA 16802, USA
6 Department of Physics and Astronomy, John Hopkins University, Baltimore, MD 21218, USA
7 Department of Physics, University of Warwick, Coventry CV4 7AL, UK
8 National Radio Astronomy Observatory, Charlottesville, VA 22903,
USA
9 Department of Physics, University of Wisconsin, Whitewater, WI 53190,
USA
10 MIT Kavli Institute for Astrophysics and Space Research and Department of Physics, Massachusetts Institute of Technology, Cambridge, MA
02139, USA
11 Centre for Astrophysics Research, STRI, University of Hertfordshire,
Hatfield AL10 9AB, UK
12 Department of Physics, Purdue University, West Lafayette, IN 47907,
USA
13 Jet Propulsion Laboratory, California Institute of Technology, Pasadena,
CA 91109, USA
14 Spitzer Science Center, California Institute of Technology, Pasadena,
CA 91125, USA
15 Department of Astronomy and Astrophysics, University of Toronto,
Toronto, ON M5S 3H4, Canada
† Current address: Department of Physics, Astrophysics, University of Oxford, Denys Wilkinson Building, Oxford, OX1 3RH, UK
‡ Current address: Lincoln Laboratory, Massachusetts Institute of Technology, Lexington, MA 02420-9108, USA
From 1996 to 1999, the Advanced Satellite for Cosmology and
Astrophysics (ASCA) performed the ASCA Galactic plane survey (AGPS), which was designed to study 40 deg2 of the Xray sky, over the Galactic coordinates |l| . 45◦ and |b| . 0◦ .4,
in the 0.7 − 10 keV energy range (Sugizaki et al. 2001). This
survey resulted in a catalog of 163 discrete X-ray sources with
X-ray fluxes between Fx ∼ 10−13 and 10−11 erg cm−2 s−1 , many
of which are much harder and more absorbed than any other
X-ray source previously detected in the Galactic plane. While
the AGPS yielded the first ever log N − log S distribution of
hard (2 − 10 keV) Galactic plane X-ray sources, ASCA’s limited spatial resolution (30 ) and large positional uncertainty (10 )
left > 100 of the AGPS sources unidentified. Even in the era
of the Chandra X-ray Observatory and the XMM-Newton telescope, a substantial fraction of the AGPS source catalog, and
therefore a large fraction of the Galactic plane X-ray population, still remain unidentified.
For the last few years, new and archival multi-wavelength data
have been used to improve the general understanding of the
Galactic X-ray sources detected in the AGPS. Recent work
has demonstrated that unidentified ASCA sources represent
a whole range of unusual objects. For example Gelfand &
Gaensler (2007) used new and archival Chandra and XMM
observations to identify the AGPS source AX J155052–5418
(also known as 1E 1547.0–5408) as a magnetar sitting at the
center of a faint and small, previously unidentified, radio supernova remnant (SNR) called G327.24–0.13. Investigations
of archival XMM data allowed Kaplan et al. (2007) to identify the AGPS source AX J183528–0737 as a likely sym-
2
biotic X-ray binary (SyXB) comprising of a late-type giant
or supergiant and a neutron star (NS) with a 112s pulse period. Gaensler et al. (2008) identified the AGPS source AX
J172105–3726 as the X-ray emission associated with the radio SNR G350.1–0.3. The XMM X-ray spectrum, combined
with the presence of non-thermal, polarized, radio emission,
showed G350.1–0.3 to be a very young and luminous SNR. A
central compact object was also resolved in these X-ray observations and identified as a NS. XMM (Funk et al. 2007)
and Chandra (Lemiere et al. 2009) observations have demonstrated that the AGPS source AX J164042–4632 is an Xray pulsar wind nebula (PWN) located at the center of the
radio SNR G338.3–0.0. Chandra results, discussed in Anderson et al. (2011), have revealed that two AGPS sources,
AX J163252–4746 and AX J184738–0156, are massive stars
in colliding wind binaries (CWBs). New Chandra, XMM,
and ATCA observations have also been used to identify the
AGPS source AX J162246–4946 as the radio and X-ray emitting magnetar, PSR J1622–4950, and have exposed the likely
X-ray transient nature of this source (Anderson et al. 2012).
These identifications over the last 8 years have therefore
demonstrated that many of the unidentified AGPS sources are
unusual and rare Galactic plane X-ray objects.
The most comprehensive X-ray survey to-date, in terms of
area coverage, was performed by the ROSAT X-ray Satellite (for example see Voges et al. 1999), which mapped the
soft X-ray source population (0.1 − 2.4 keV) down to a flux
sensitivity of a few 10−13 erg cm−2 s−1 . Projects that focused on the ROSAT data covering the Galactic plane (e.g.
the ROSAT Galactic Plane Survey; Motch et al. 1997, 1998)
demonstrated that stars and AGN dominate the soft X-ray
sky. However, performing a similar Galactic plane survey
to include those sources with energies up to 10 keV, sensitive to the Fx ∼ 10−13 to ∼ 10−11 erg cm−2 s−1 flux range,
would be impractical to achieve with the current X-ray telescopes Chandra and XMM due to their limited fields of view.
Astronomers have therefore had to rely upon characterizing
the distribution of the harder X-ray source populations within
much smaller regions of the Galactic plane (e.g. Hands et al.
2004; Ebisawa et al. 2005; Grindlay et al. 2005). For example, Motch et al. (2010) used the XGPS (Hands et al. 2004)
to determine the contributions of active stellar coronae and
accreting X-ray source populations in the Galactic plane for
Fx . 10−12 erg cm−2 s−1 . The Chandra Multiwavelength Plane
survey (ChaMPlane; Grindlay et al. 2005) has now surveyed
7 deg2 of the Galactic plane and bulge with Chandra (van den
Berg et al. 2012), identifying the contributions of magnetic
cataclysmic variables (CVs) to the Galactic ridge X-ray emission (Hong 2012).
The key to obtaining a complete understanding of the Galactic plane X-ray source populations, from 0.3 − 10 keV, that
make up the Fx ∼ 10−13 to 10−11 erg cm−2 s−1 X-ray flux range
is to identify the unidentified AGPS sources, as ASCA covered a much larger area of the Galactic plane (∼ 40 deg2 ) than
other X-ray surveys (for example the XGPS and ChaMPlane;
Hands et al. 2004; Motch et al. 2010; Grindlay et al. 2005;
van den Berg et al. 2012). In order to identify the AGPS
sources, the Chasing the Identification of ASCA Galactic
Objects (ChIcAGO) survey was conceived. In this survey the
subarcsecond capabilities of Chandra are used to localize the
unidentified AGPS sources listed by Sugizaki et al. (2001).
Once the positions of these sources have been determined,
an extensive multi-wavelength program is activated, which is
aimed at determining the identities of the sources and the nature of their X-ray emission.
In this paper, we present the results of Chandra observations of 93 unidentified AGPS sources, along with the multiwavelength follow-up that has allowed the identification of
optical, infrared and radio counterparts. Section 2 explains
the Chandra observing strategy employed to localize the
unidentified AGPS sources. To begin the identification process, we automated the Chandra data analysis and preliminary multi-wavelength follow-up, which involves comparisons with existing optical, near-infrared (NIR) and infrared
(IR) surveys. X-ray spectral modeling using “quantile analysis” (Hong et al. 2004) and Cash (1979) statistics, and further
multi-wavelength observations in the optical, infrared and radio bands required to ultimately classify each source, are also
described. Section 3 details the results of each AGPS position observed with Chandra. These results include details on
the individual X-ray sources detected, the parameters of their
likely X-ray spectral shapes, and the names and magnitudes
of their infrared, optical and radio counterparts. The possibility of short term variability or periodicity is also explored.
In Section 4, we discuss the AGPS sources that have been
identified through a visual inspection of radio Galactic plane
surveys. The X-ray fluxes and NIR and IR magnitudes of the
remaining unidentified sources, reported in Section 3, are then
used to conduct X-ray and infrared population statistics. Resulting flux and color-color diagrams allow the identification
of likely Galactic plane X-ray populations with infrared counterparts. This analysis is followed by a discussion of particularly interesting individual sources that have been identified as
a result of this work. The final part of this section includes a
tabulated summary of all the 163 AGPS sources along with
their confirmed identifications (obtained from the literature
and the present paper) or their tentative identifications that are
based on our ChIcAGO survey statistical results. In Section
5 we summarize the results from this paper, with a particular
focus on our statistical findings.
2. METHOD
2.1. Chandra Observations
The main goal of the ChIcAGO survey is to localize the
positions of the unidentified AGPS sources, so that multiwavelength follow-up can be used to identify them. It is therefore necessary to design an experiment that will allow each
source to be localized precisely enough to identify counterparts in the crowded Galactic plane. Chandra can provide
subarcsecond localization as it has an intrinsic astrometric
precision accuracy of 0.00 6 at 90% confidence within 20 of the
aim-point (Weisskopf et al. 2003).
For all but the brightest targets, Chandra’s Advanced CCD
Imaging Spectrometer (ACIS; Garmire et al. 2003) was used
as it provides simultaneous positional, temporal and spectroscopic information. The ACIS-S configuration was chosen as
it fully encompasses the AGPS positional uncertainties of up
to 30 (Sugizaki et al. 2001). (The aimpoint of the ACIS-I configuration is near a chip gap.) The High Resolution Camera
(HRC; Murray 2000) in the I focal plane array was used to
observe those sources with a predicted ACIS count-rate > 0.2
counts s−1 , to avoid positional, spectral, and temporal degradation associated with pile-up (Davis 2001).
T HE C H I C AGO S URVEY
At Chandra’s high angular resolution, only a small number
of X-ray counts are required to localize each source sufficiently to overcome confusion from IR field stars in the Galactic plane. We first considered the number density of such
stars in the Ks -band at low Galactic latitudes. Figure 24 of
Kaplan et al. (2004) shows that 0.2 stars arcsec−2 are expected with a magnitude Ks . 19. For there to be a < 25%
chance of random alignment of the Chandra source with an
infrared field star of this magnitude, a total astrometric error < 0.00 7 is required. Using 2MASS as a guide, given its
extremely high positional precision (0.00 1 1σ error) and Chandra’s 90% absolute astrometry error of 0.00 6, a centroiding error of < 0.00 4 with 95% accuracy is required for Chandra. The
Chandra Interactive Analysis of Observations (CIAO)18 software tool wavdetect (Freeman et al. 2002) was chosen to
detect the point sources in our fields. Equation (5) of Hong
et al. (2005) provides the 95% confidence position error circle of a point source detected with wavdetect for a given
number of source counts at a given off axis angle. At the
maximum off-axis angle expected for an ASCA source localization (< 30 ), ∼ 100 X-ray counts are required to ensure that
a source’s centroiding error is below 0.00 4.
Using the count rates and power-law spectral fits calculated by
Sugizaki et al. (2001) for each AGPS source and the Chandra
Proposal Planning Toolkit (PIMMS)19 , the exposure time required to detect ∼ 100 counts with Chandra for each source
was estimated. For those AGPS sources that were too faint
for Sugizaki et al. (2001) to calculate spectral fit parameters,
an absorbed power-law model with a photon index Γ = 2 and
an absorption NH = 1022 cm−2 was used, which are representative values of a non-thermal X-ray source and typical Galactic
plane absorption.
the original AGPS sources X-ray flux range (see Sections 3.2
and 3.3).
2.2. ChIcAGO Multi-wavelength Analysis Pipeline (MAP)
It is crucial to the efficiency of the project to automate the
analysis of the Chandra observations, such as the detection
and extraction of sources, as well as the search for multiwavelength counterparts. We therefore created the ChIcAGO
Multi-wavelength Analysis Pipeline (MAP) for this task.
ChIcAGO MAP takes the ACIS-S or HRC-I Chandra observation of an AGPS source field and detects and analyzes all
point sources within 30 , equivalent to the largest likely position error, for the original AGPS source positions supplied
by Sugizaki et al. (2001). From hereon we refer to all point
sources detected in the Chandra observations of the AGPS
fields as “ChIcAGO sources”. The X-ray analysis component of this pipeline uses the CIAO software, version 4.3, with
CALDB version 4.5.5, and follows standard reduction recipes
given in the online CIAO 4.3 Science Threads.20
ChIcAGO MAP carries out the following steps, all of which
are explained in more detail below. These steps apply to both
ACIS-S and HRC-I datasets unless otherwise stated.
• An image of the original ASCA detection of the AGPS
source is created (for example see the top image of Figure 1).
• The CIAO tool chandra_repro is run to reprocess
the Chandra data.
• The new event file is filtered to only include photons
with energies in the range 0.3 − 8.0 keV.
In order to select the AGPS source candidates to be observed with Chandra, each source was investigated individually. First those AGPS sources that have already been conclusively identified, either by Sugizaki et al. (2001) or by other
groups in the literature, were removed from the Chandra target list. Based on this criteria, a total of 43 AGPS sources
were identified and therefore rejected for Chandra follow-up
(these sources are described in Appendix A). The ASCA images of each of the remaining unidentified AGPS sources were
then studied to determine if any sources appeared to be too extended for Chandra to successfully localize in a short amount
of time. These sources were also rejected for Chandra followup. The remaining, unidentified AGPS sources, were then prioritized for Chandra follow-up based on their absorbed X-ray
flux or count-rate that was listed by Sugizaki et al. (2001).
• The CIAO tool wavdetect is used to detect all Xray point sources (ChIcAGO sources) within 30 of the
AGPS position. A Chandra image is then created for
each ChIcAGO source (for example see the bottom image of Figure 1). If no sources are detected, ChIcAGO
MAP ends.
• The position, source counts, and associated errors are
calculated for each ChIcAGO source detected. If the
dataset is an ACIS-S observation then the total counts
are obtained in the 0.3 − 8.0, 0.5 − 2.0, and 2.0 − 8.0 keV
energy ranges, and the energy quartiles (E25 , E50 , and
E75 ), which are used in quantile analysis (see Section
2.3.1), are calculated.21
A total of 93 AGPS sources have been observed with Chandra as part of the ChIcAGO survey, of which 84 were imaged
with ACIS-S and 9 were imaged with HRC-I. The ChIcAGO
Chandra observations took place over a three and a half year
period, from 2007 January to 2010 July. The Chandra exposure times ranged from ∼ 1 − 10 ks. All the details of these
Chandra observations are listed in Table 1. The initial automated analysis of these Chandra observations was conducted
using the ChIcAGO Multi-wavelength Analysis Pipeline, described in Section 2.2. We then performed a more detailed Xray analysis and counterpart study for those 74 sources with
> 20 X-ray counts, as such sources are approximately within
18
19
http://cxc.harvard.edu/ciao/index.html
http://cxc.harvard.edu/toolkit/pimms.jsp
3
• The CIAO tool specextract is run on ACIS-S
datasets to obtain the source and background spectrum
files and their corresponding redistribution matrix file
(RMF) and the ancillary response file (ARF) for each
ChIcAGO source. These files are used in quantile analysis and spectral modelling (see Section 2.3).
• A timing analysis is conducted on each ChIcAGO
source (detected with either the ACIS or HRC instruments) to search for short term variability and periodicity.
20
http://cxc.harvard.edu/ciao4.3/threads/index.html
The HRC instrument has very poor spectral resolution so this, and the
following step, are not conducted on these datasets.
21
4
– A light-curve with 8 bins is constructed using the
CIAO tool dmextract. The χ2 is calculated for
this light-curve in order to test for short-term variability (e.g. Figure 2).
– The Z12 statistic is calculated to search for sinusoidal periodicity (Buccheri et al. 1983). This
process creates a power spectrum and folded light
curve (e.g. Figure 3), which predicts the most
likely pulsed frequency, its corresponding power,
and the probability that the power is random
noise.
• Multi-wavelength follow-up and catalog searches are
conducted to identify likely optical, infrared, and radio
counterparts to each ChIcAGO source.
– The USNO B1 (Monet et al. 2003), 2MASS PSC
(Skrutskie et al. 2006), and GLIMPSE I and II
(Benjamin et al. 2003) catalogs are accessed to
obtain a list of all optical and infrared sources
within 400 of the ChIcAGO source’s wavdetect
position.
– Small sized (60 by 60 ) image cutouts, centered
on the ChIcAGO source’s wavdetect position,
are obtained from the 2nd Digitized Sky Survey
(Red: DSS2R and Blue: DSS2B; McLean et al.
2000), 2MASS, and the GLIMPSE I and II surveys. A 300 by 300 radio image cutout is obtained
from the Sydney University Molonglo Sky Survey
(SUMSS; Bock et al. 1999). Examples of all the
image cutouts can be found in Figures 4 and 5.
ChIcAGO MAP first generates an image of the AGPS source
as originally detected by the Gas Imaging Spectrometer (GIS;
Ohashi et al. 1996) onboard ASCA. The GIS has a circular
field-of-view with a 500 diameter. The top image of Figure 1 shows the ASCA GIS detection of the AGPS source AX
J144701–5919. We have chosen AX J144701–5919 as the
example source for illustrating the output of ChIcAGO MAP
because it was the first AGPS source observed with Chandra as part of the ChIcAGO survey, and it is also an interesting source with a bright counterpart (as demonstrated by its
identification as an X-ray emitting WR star in Anderson et al.
2011).
ChIcAGO MAP reprocesses all of the Chandra observations,
both ACIS and HRC, using the CIAO chandra_repro
script, which creates a new level=2 event file and bad pixel
file. The Chandra ACIS data are filtered to only include
events with energies in the range 0.3 − 8.0 keV in order to
avoid high-energy and cosmic ray particle backgrounds.
We have chosen to optimize ChIcAGO MAP for the detection
of point sources as our short Chandra observations (< 10 ks)
are not very sensitive to extended sources. ChIcAGO MAP
uses the CIAO wavelet detection algorithm, wavdetect,
which we have set to search for all sources with wavelet scales
of radii 1, 2, 4, 8 and 16 pixels. This does, however, introduce
a source selection bias as it is possible that AGPS sources that
were unresolved with the ASCA PSF could be extended, and
therefore resolvable with Chandra. Re-running ChIcAGO
MAP using wavdetect with larger scales more appropriate
for extended sources, or using the CIAO Voronoi Tessellation and Percolation source detection algorithm vtdetect
Figure 1. X-ray images of AX J144701–5919 as output by ChIcAGO MAP.
Top: The ASCA GIS detection of the AGPS source AX J144701–5919.
The circular field-of-view has a 500 diameter and the position of this AGPS
source, as listed by Sugizaki et al. (2001), is indicated by the black crosshair. Bottom: The 30 radius field-of-view of the Chandra observation of AX
J144701–5919, which is centered on the position of this AGPS source listed
by Sugizaki et al. (2001). The one ChIcAGO source detected in this field is
indicated by a black cross-hair, and is likely the Chandra counterpart to AX
J144701–5919.
(Ebeling & Wiedenmann 1993), could be conducted in the
future to detect extended sources in the ChIcAGO Chandra
images.
ChIcAGO MAP utilizes wavdetect to detect all sources
within 30 of the original ASCA position (for example see the
Chandra detection of AX J144701–5919 in the bottom image
of Figure 1). This search radius is based on the position accuracy and spatial resolution of ASCA and therefore designed
to ensure that the majority of contributing X-ray sources are
encompassed. (However, it is also possible that there are associated X-ray sources beyond 30 from the AGPS position.
This could be due to the inaccuracy of the ASCA positions of
those sources that are blended or near the edge of the field-ofview. This is further explored in Section 3.1 and Appendix B.)
T HE C H I C AGO S URVEY
The position of each ChIcAGO source as output by
wavdetect is obtained and Equation (5) of Hong et al.
(2005) is used to calculate the 95% confidence position error
circle.22 This wavdetect error is then added in quadrature
to the absolute astrometry error of Chandra to obtain the total
position error of each ChIcAGO source.
The source regions used to calculate the total number of
source counts, which are centered on the source position as
output by wavdetect, have a radius equivalent to 95% of
the point-spread function (PSF) at 1.5 keV. The background
subtraction is performed using an annulus whose size is between two and five times the above 95% PSF radius, centered
on the source position. Given the low number of counts detected, usually < 100, the 1σ lower and upper confidence limits of the total number of counts are calculated using Gehrels
(1986) statistics. The following energy based analysis is then
performed on the ACIS-S observations. The total number of
counts are calculated for the 0.3 − 8.0, 0.5 − 2.0, and 2.0 − 8.0
keV energy ranges. ChIcAGO MAP then uses the extracted
ACIS-S counts and corresponding energies to calculate the
25%, 50% and 75% photon fractions (E25 , E50 and E75 ), the
energies below which 25%, 50% and 75% of the photon energies are found, respectively. These median (E50 ) and quartile
(E25 and E75 ) values can immediately characterize the hardness of a source without using conventional hardness ratios,
which are not versatile enough to account for diverse X-ray
spectral types in the Galactic plane. These quartile fractions
can then be used to employ quantile analysis (Hong et al.
2004), which uses a quantile based color-color diagram to
classify spectral features and shapes of low count sources (see
Section 2.3.1).
The CIAO tool, specextract, is also run on the ACISS detected ChIcAGO sources to generate source and background spectrum files and their corresponding RMF and the
ARF. These files are used to perform spectral interpolation
with quantile analysis and to conduct spectral modelling and
fitting with the CIAO package Sherpa. Further details on the
spectral investigations of the ChIcAGO sources can be found
in Section 2.3
ChIcAGO MAP then performs a timing analysis on all the
ChIcAGO sources, detected with either the ACIS or HRC instruments, to search for evidence for short term variability
and periodicity. In each case a light-curve is extracted using
dmextract where the counts are divided into 8 bins (for
example see Figure 2). The Gehrels approximation to confidence limits for a Poisson distribution is used to estimate
the errors as there are < 20 X-ray counts in each bin. The
χ2 statistics are adopted to test for variability (for example
see Gaensler & Hunstead 2000). (It should be noted that as
dmextract uses the upper (larger) Gehrels confidence limit
22 This equation was constructed by running wavdetect on ACIS-I and
ACIS-S data. It is therefore unknown whether this position error equation
is applicable to the positions calculated from running wavdetect on HRC
data sets. However, since the wavdetect algorithm is not instrument specific, it is likely that this equation estimates reasonable errors for sources
detected in HRC observations.
to estimate the count-rate errors, the resulting χ2 output by
ChIcAGO MAP may be underestimated.) For 7 degrees of
freedom, χ2 & 24.3 is required for a source to be considered
variable at 99.9% confidence.
AX J144701-5919 LIGHT-CURVE
0.11
0.10
0.09
NET_RATE (counts/s)
In many cases more than one X-ray source could have been
contributing to the total X-ray flux from an AGPS source originally detected with ASCA. (Note this is not the case for the
example of AX J144701–5919.) The positional accuracy of
wavdetect has been well investigated and tested in previous Chandra surveys (i.e. ChaMPlane; Hong et al. 2005).
5
0.08
0.07
0.06
0.05
0.04
0.03
0.02
1000
1200
1400
1600
1800
2000
2200
TIME (s)
Figure 2. The Chandra ACIS-S light-curve of the ChIcAGO source AX
J144701–5919 as output by ChIcAGO MAP. This ChIcAGO source does not
exhibit evidence for short-term variability as its resulting χ2 = 3.4 for 7 degrees of freedom is below the confidence threshold of 99.9%.
After correcting the photon arrival times to the Solar System
barycenter, the target source is then investigated for evidence
of periodicity using the Zn2 test (Buccheri et al. 1983), equivalent to the Rayleigh statistic when n, the chosen number of
harmonics, is set to 1. ChIcAGO MAP uses n = 1 for the sake
of simplicity and because such a test is sensitive to sinusoidal
distributions. Z12 has a probability density function equivalent
to the χ2 statistic with 2 degrees of freedom. ChIcAGO MAP
searched for periodicity down to 6.48s (twice the frame-time
resolution; Weisskopf et al. 2003) for sources detected with
ACIS, and down to 0.01s for sources detected with HRC.23 A
power spectrum (power vs. frequency) and folded light curve
(counts per bin vs. phase) of each source is generated, predicting the pulsed frequency of the highest Z12 power, and the
probability that this power was random noise for a given number of trials (for example see Figure 3). A 99.9% confidence
was required for a source to have a significant level of periodicity, which corresponds approximately to Z12 & 26 and
Z12 & 36 for ACIS and HRC observations, respectively.
It is also possible that many of the AGPS sources are transient or undergo long-term variability, so have changed significantly in flux since the original ASCA observations. The detailed analysis of any periodic, variable, and transient sources
is beyond the scope of this paper. We only flag those source
that may fit into one of the above categories for the purpose
of future investigations.
The next step in the ChIcAGO identification process is to
search for multi-wavelength counterparts to the ChIcAGO
sources. ChIcAGO MAP accesses the US Naval Observatory
B Catalog, version 1.0 (USNO B1, visual magnitude bands B,
R, and I; Monet et al. 2003), the Two Micron All Sky Survey
Point Source Catalog (2MASS PSC, near-infrared magnitude
23 The lower-limit of 0.01s for the HRC observations is chosen because a wiring error in the detector degrades the time resolution accuracy from 16µs to the mean time between events.
See
http://cxc.harvard.edu/proposer/POG/html/chap7.html#sec:hrc_anom
6
SUMSS, which is a survey conducted with the Molonglo Observatory Synthesis Telescope (MOST) and has a resolution
of 4300 × 4300 cosec|dec| (Bock et al. 1999).26 An example of
all the image cutouts generated by ChIcAGO MAP for AX
J144701–5919 can be seen in Figures 4 and 5.
2.3. ChIcAGO Sources Spectral Investigation
Deducing the best spectral model fit to the ChIcAGO sources
is difficult using standard X-ray spectral fitting techniques due
to the small number of X-ray source counts detected in the
Chandra observations (usually < 100). We therefore implement two different techniques for predicting the best spectral
parameters for the brighter (> 20 X-ray counts) ChIcAGO
sources. The first technique is “quantile analysis" (Hong et al.
2004), which has been recently developed to address some
of the problems associated with spectral modeling of sources
with low number statistics. Quantile analysis allows for the
interpolation of likely spectral shapes of X-ray sources with as
few as 10 counts. The second technique is utilizing the CIAO
spectral fitting tool Sherpa to obtain best fit spectral parameters using Cash (1979) statistics. These statistics are based
on Poisson distributed data and are therefore ideal for modeling spectra with a limited number of source counts. Both
methods are described in detail below.
2.3.1. Quantile Analysis
The power spectrum and folded light curve resulting from a Z12
Figure 3.
statistical search for periodicity from AX J144701–5919 as output by ChIcAGO
MAP. Top: The power spectrum (power vs. frequency (Hz)) of AX J144701–
5919. The power spectrum peaks at a value of Z12 = 14.4 at a frequency of
0.1378 Hz. The probability of this power being random noise is 0.16. It is
therefore unlikely to be a real signal. Bottom: The folded light curve (counts
per bin vs phase) that has been folded at 0.1378 Hz.
bands J, H, and Ks ; Skrutskie et al. 2006), and the Galactic Legacy Infrared Mid-Plane Survey Extraordinaire I and
II Spring 07’ Catalogs (highly reliable) and Archives (more
complete, less reliable) (GLIMPSE, infrared magnitude bands
3.6, 4.5, 5.8, and 8.0 µm; Benjamin et al. 2003) to obtain a
list of all the optical and infrared sources within 400 of the
wavdetect position of each ChIcAGO source. The information extracted from these surveys includes the position of
the source, the offset from the Chandra position and the magnitudes listed in the given survey or dataset.24
Small sized images cutouts (60 by 60 ) from optical and infrared
surveys, centered on the ChIcAGO source wavdetect position, are also downloaded to enable a visual inspection
of likely counterparts and their surrounding environments.
The B and R magnitude band images are obtained from the
2nd Digitized Sky Survey (Blue: DSS2B and Red: DSS2R;
McLean et al. 2000) and the J, H, and K magnitude band images are obtained from 2MASS. Image cutouts of the infrared
magnitude bands 3.6, 4.5, 5.8 and 8.0 µm are obtained from
the GLIMPSE I and II, version 3.5, surveys.25 A 300 by 300
image cutout of the 843 MHz radio sky is also generated from
24
The catalog information is downloaded via a generic URL from
the VizieR Service (http://vizier.cfa.harvard.edu/viz-bin/VizieR) and the
NASA/IPAC Infrared Science Archive (http://irsa.ipac.caltech.edu/).
25 http://irsa.ipac.caltech.edu/data/SPITZER/GLIMPSE/
Quantile analysis uses predetermined fractions of the total
number of energy source counts, such as the median (E50 ) and
quartile energies (E25 and E75 ), to construct a quantile-based
phase space that can be overlayed with grid patterns of common spectral models. This quantile phase space is more sensitive to the wide range of Galactic X-ray sources than those
constructed from conventional hardness ratios. This is because there is no count-dependent sensitivity bias toward any
spectral type, which is inherent to the choice of sub-energy
bands in the conventional spectral hardness or X-ray color
analysis. In the ChIcAGO survey, quantile analysis is adopted
to calculate potential spectral shapes of the ChIcAGO sources.
The ACIS-S detected ChIcAGO sources selected for quantile
analysis have > 20 (net) X-ray counts in the 0.3 − 8.0 keV
energy band, as these are likely to be bright enough to be
the original AGPS sources (see Section 2.1). The net counts
were obtained by summing the total number of counts inside
a source region that is 6 times the error radius in size and subtracting the background normalized counts calculated from an
annulus that has an outer radius of ∼ 1500 with the source region subtracted. The three quartiles (E25 , E50 , and E75 ) and
their corresponding errors were calculated as outlined by
Hong et al. (2004).
The quantile phase space, suggested by Hong et al. (2009,
see their Figure 4), used to calculate the likely spectral
shapes, was constructed for each ChIcAGO source. This
phase space consists of the normalized logarithmic median
(log(E50 /Elow )/log(Ehigh /Elow )) and the normalized quartile
ratio (3 × (E25 − Elow )/(E75 − Elow )), where Elow = 0.3 keV and
26 The images from the DSS2R, DSS2B, 2MASS and SUMSS surveys
are downloaded using a generic URL from the virtual observatory SkyView,
which is a service of the Astrophysics Science Division at NASA/GSFC and
the High Energy Astrophysics Division of the Smithsonian Astrophysical Observatory (SAO), http://skyview.gsfc.nasa.gov/
T HE C H I C AGO S URVEY
7
Figure 4. The DSS2B, DSS2R, 2MASS and SUMSS image cutouts of the region surrounding the AGPS source AX J144701–5919, which has been localized by
Chandra, as output by ChIcAGO MAP. In all images the Chandra position of AX J144701–5919 is indicated by a black cross-hair. The survey name and filter
band of each image cutout is listed at the top of each Figure.
Ehigh = 8.0 keV, equivalent to the energy range explored. The
logarithmic median phase space takes advantage of the higher
sensitivity at low energies in typical X-ray telescope CCDs,
while keeping the spectral discernibility more or less uniform throughout the full range of the phase space. In order
to compensate for the spatial change of the detector response
in Chandra/ACIS, the RMF and the ARF, appropriate to the
observed location of each ChIcAGO source in the CCD, are
calculated using the CIAO tools.
The data points of the ChIcAGO sources in the quantile diagram were compared with simple power-law and thermal
bremsstrahlung spectral models to extract the most plausible
spectral parameter values for each source. It should be noted
that quantile analysis cannot evaluate which model is more
likely unless the estimated parameters of the model turn out
to be unphysical (e.g. Γ > 4). The estimate of the spectral
parameters are limited to −2 ≤ Γ ≤ 4 for a power law model
and 0.1 keV ≤ kT ≤ 10 keV for a bremsstrahlung model. The
explored extinction (NH ) covers the range 0.01 − 100 × 1022
cm−2 . If the data point for a source in quantile phase space sits
outside of the model grid set by these parameter ranges, the
model is considered incompatible with the observed spectrum
of the source. The quantile errors allow the spectral parameter uncertainties to be calculated for each ChIcAGO source
(Hong et al. 2004).
2.3.2. Spectral Modeling
8
Figure 5. As for Figure 4, but showing the GLIMPSE 3.6, 4.5, 5.8, and 8.0 µm bands.
The spectral modeling of the ChIcAGO sources was conducted using the CIAO 4.5 spectral fitting package Sherpa
with the statistics set to the XSpec (Dorman & Arnaud 2001)
implementation of Cash (1979) statistics. Cash statistics apply a maximum likelihood ratio test that can be performed
on sources with a low number of source counts per bin. We
chose to restrict all spectral modeling to those ChIcAGO
sources with > 50 X-ray counts as attempted modeling of
those sources with less counts usually did not converge.
Cash statistics cannot be performed on a background subtracted spectrum. The source and background spectrum must
instead be modeled simultaneously. However, in the case
of the Chandra observations of ChIcAGO sources the background is extremely low and cannot be described by a generic
spectral model. As a result attempting to model the background spectrum does not improve the overall spectral fit. We
therefore only model the source spectrum of the ChIcAGO
sources.
Both an absorbed power law and an absorbed thermal
bremsstrahlung model are applied to the ChIcAGO source
spectra so that they can be directly compared to the quantile analysis spectral interpolation results. The parameter errors are calculated using the Sherpa “projection" function,
which estimates the 1σ confidence intervals. The absorbed
and unabsorbed flux (plus errors) are calculated using the
Sherpa function “sample_flux", which is new to CIAO 4.5.
The overall goodness of fit measure is defined by the value of
the Cash statistic divided by the number of degrees of freedom
and should be of order 1.
2.4. Multi-wavelength Follow-up Observations
While the X-ray morphology and spectrum can provide information on the nature of a ChIcAGO source, the key to identification is usually through an extensive multi-wavelength
follow-up campaign. ChIcAGO MAP identifies the possible
optical and infrared counterparts in existing multi-wavelength
Galactic plane surveys. There are, however, many cases
where the counterparts are too faint to be detected in these
surveys due to the high absorption in the Galactic plane. It
is also possible that the high object density in the Galactic
plane may result in confusion with nearby sources. In these
cases, further optical and infrared photometric observations
were conducted with large telescopes to obtain detections of
faint counterpart candidates and to separate likely blends. If
the first photometric observing attempt was unsuccessful at
detecting or separating a counterpart candidate then deeper
imaging using longer exposure times was conducted. Those
X-ray sources that remain undetected at optical and infrared
wavelengths will need to be further investigated in the X-ray
band or at other wavelengths.
The radio wavelength band is also a useful diagnostic for identifying X-ray sources in the Galactic plane. Comparing the Xray source positions with radio surveys can indicate if there is
a likely radio counterpart or whether the X-ray source lies in
a diffuse region of radio emission in the Galactic plane. Interferometric radio observations of a small subset of ChIcAGO
sources were obtained in order to resolve confusing regions
of radio emission and allow for the detection or confirmation
of compact radio counterparts.
T HE C H I C AGO S URVEY
2.4.1. Optical and Near Infrared Observations with Magellan
The optical and NIR photometric observations presented in
this paper were obtained using instruments on the twin 6.5m,
Baade and Clay, Magellan telescopes, located at Las Campanas Observatory, Chile. The NIR photometry, 1 − 2.5µm,
was obtained using the Persson’s Auxiliary Nasmyth Infrared
Camera (PANIC; Martini et al. 2004; Osip et al. 2008) on
Baade. PANIC was used primarily to detect the counterparts
of ChIcAGO sources with no cataloged counterparts or to utilize this instrument’s high angular resolution to eliminate possible blendings. Observations were obtained in the J, H and
Ks photometric bands, using short exposures (10 − 30s) that
were dithered to account for the high sky background inherent to NIR observations.
The PANIC NIR imaging data were reduced using the Image Reduction and Analysis facility (IRAF; Tody 1986, 1993)
and the PANIC Data Reduction Package for IRAF (Martini
et al. 2004), taking into account the corresponding darks, sky
flats and bad pixel maps obtained for each respective night.
The absolute astrometry for the PANIC observations was derived using the 2MASS PSC and the Graphical Astronomy
and Image Analysis Tool (GAIA; Draper et al. 2009). The
positional accuracy of the 2MASS PSC is 0.00 1 (1σ, Skrutskie
et al. 2006), and since there are usually many 2MASS sources
in the field, a similar order of astrometric accuracy at the target positions was reached. SExtractor (Bertin & Arnouts
1996) was used for source detection, and the calibration of
the photometry was performed by applying 2MASS PSC photometry to known 2MASS sources in the target fields. No correction to the atmospheric extinction was applied as this effect
is very small in the NIR (∼ 0.06 magnitudes in the H-band).
The errors were obtained by comparing the NIR-magnitudes
with 2MASS PSC magnitudes, and reflected average deviations from the 2MASS catalog magnitudes.
Optical photometric observations of the counterparts were obtained utilizing several Magellan instruments depending on
availability. These included the Inamori Magellan Areal Camera and Spectrograph (IMACS; Dressler et al. 2006; Osip et al.
2008) and the Raymond and Beverly Sackler Magellan Instant
Camera (MagIC; Osip et al. 2008) on the Baade telescope.
These instruments provide access to different photometric filters including Bessel B, V and R, and CTIO I.
The IMACS B, V , R and I imaging data were reduced using
IRAF, in which the data were trimmed, overscan-corrected
and flat-fielded. A dark current subtraction was not applied
since the dark images showed it to be negligible. Standard
stars were observed throughout in several bands, although the
weather during some of the observing nights varied. The
absolute astrometry was again computed using GAIA with
comparisons to the USNO B1 Catalog or the 2MASS PSC.
The photometry of each counterpart was calculated using
SExtractor and was calibrated using the USNO B1 Catalog.
MagIC observations were obtained in the V , R, and I bands.
Short 30 s exposures were obtained in each filter, which were
later combined to make sure that the brighter stars (used for
astrometric referencing) were not saturated. These data were
then reduced following standard procedures in IRAF: overscan subtraction for each amplifier, flatfielded using dome
flats, and the separate exposures combined. The astrometry
was applied by referencing the observations to the 2MASS
9
PSC, resulting in an rms residual of 0.00 1 in each coordinate.
Photometric calibration was derived using observations of the
Stetson (2000) standard fields. The measured photometry for
the airmass terms appropriate to Las Campanas Observatory
were corrected and the zero-points with scatters of 0.02 magnitudes in each filter were obtained. Similarly to the PANIC
and IMACS observations, the photometry of each counterpart
was then measured using SExtractor.
2.4.2. Radio follow-up and ATCA Observations
Radio survey data already exist for all of the AGPS source
regions, via the first and second epoch Molonglo Galactic
Plane Surveys at 843 MHz (MGPS1 and MGPS2 respectively,
4300 × 4300 cosec|dec| resolution; Green et al. 1999; Murphy
et al. 2007), the 90cm Multi-configuration Very Large Array
Survey of the Galactic Plane (4200 resolution; Brogan et al.
2006), The Multi-Array Galactic Plane Imaging Survey at 1.4
GHz (MAGPIS, 600 resolution; Helfand et al. 2006), and the
Very Large Array (VLA) Galactic Plane Survey at 1.4 GHz
(VGPS, 10 resolution; Stil et al. 2006). To search for possible
radio counterparts we first visually inspected the above surveys at the position of each ChIcAGO source. Any coincident
radio emission was then categorized (see Section 3.4).
Follow-up Australia Telescope Compact Array (ATCA) observations were conducted to identify the nature of any radio
counterparts to the ChIcAGO sources found through this visual inspection. The ATCA was also used to resolve any diffuse radio emission surrounding a ChIcAGO source, allowing
the detection of any underlying, compact radio counterpart.
The high resolution ATCA observations were instrumental in
confirming a positional coincidence between the radio counterpart and the Chandra position of the ChIcAGO source, to
measure accurate radio fluxes and spectral indices, to broadly
characterize variability with respect to earlier epochs, and to
constrain the object’s spatial extent. The Chandra positions of
ten ChIcAGO sources were observed with the ATCA on 2008
January 21 and on 2008 April 11. Each source was observed
for ∼ 1 hour at each of 1.4, 2.4, 4.8 and 8.6 GHz over a 12
hour period with a 6km baseline configuration.
3. RESULTS
3.1. Chandra Results
We present results on 93 APGS sources that have been observed with Chandra as part of the ChIcAGO survey. In many
cases more than one source was detected within 30 of the original AGPS source positions so, as mentioned in Section 2.2,
we will refer to these all as ChIcAGO sources. We therefore
detected a total of 253 ChIcAGO sources in these 93 Chandra observations. The naming convention we have adopted
is to call each source by the AGPS coordinate name, using
ChI as the prefix, with a suffix between 1 to i, where i is
equal to the number of sources detected in the 30 field. (The
source name order is based on the order that wavdetect
detected and output the sources in ChIcAGO MAP.) For example, two ChIcAGO sources, ChI J165646–4239_1 and ChI
J165646–4239_2, were detected with Chandra in the vicinity
of the AGPS source AX J165646–4239. These two ChIcAGO
sources are the black dots in Figure 6. The ASCA GIS detection of AX J165646–4239 is overlayed on Figure 6 in the form
of contours, demonstrating that both ChI J165646–4239_1
10
and ChI J165646–4239_2 may have contributed to the X-ray
emission originally detected for this source in the AGPS.
Figure 6. The 30 radius field-of-view of the Chandra observation of the
AGPS source AX J165646–4239, which is centered on the position of AX
J165646–4239 as listed by Sugizaki et al. (2001). Two ChIcAGO sources,
ChI J165646–4239_1 and ChI J165646–4239_2, which are black dots indicated by arrows, were detected with Chandra and are labeled on this Figure. The black contours represent the smoothed ASCA GIS detection of AX
J165646–4239 at 65%, 75%, 85%, and 95% of the peak count-rate.
The Chandra observations of the 93 AGPS sources are summarized in Table 1. This information includes the observation
identification, the date of the observation, instrument (ACISS or HRC-I), and the exposure time. Table 1 also lists the
ChIcAGO sources detected by ChIcAGO MAP within 30 of
the ASCA position and their corresponding wavdetect position, the offset of this position from the original AGPS position, the 95% wavdetect and total ChIcAGO source position error, the background corrected net counts in the 0.3−8.0,
0.5 − 2.0 and 2.0 − 8.0 keV energy ranges,27 and the median
energy quartile (E50 ) and quartile ratio (3 × (E25 − 0.3)/(E75 −
0.3)) used in quantile analysis (see Section 2.3.1).
The variability analysis performed by ChIcAGO MAP detected only one ChIcAGO source, ChI J170444–4109_1, with
a χ2 exceeding the 99.9% short term variability threshold
(χ2 = 80.6). However, this variability is not real as the ACISS detection of ChI J170444–4109_1 fell in the chip gap between the CCDs. This resulted in its light-curve displaying
the Chandra spacecraft’s built-in dither as the source moved
on and off the chip at regular intervals.28 No other ChIcAGO
source had a χ2 exceeding the 99.9% confidence threshold for
short term variability or periodicity. This does not, however,
rule out the possibility that some of these sources are periodic as the Z12 period search technique is extremely limited
for < 200 X-ray counts.
Several faint ChIcAGO sources were detected with
wavdetect in the Chandra observations that are not
27 The net counts were calculated separately for each energy range so there
are several cases where the total number of counts in the 0.3 − 8.0 keV energy
range is slightly different to the sum of counts detected in the 0.5 − 2.0 and
2.0 − 8.0 keV energy ranges. These differences are due to rounding errors, as
well as the exclusion of very soft counts that were detected between 0.3 − 0.5
keV. (The 0.3 − 0.5 keV energy range was excluded as the 0.5 − 2 keV energy
band is more commonly used than the 0.3 − 2 keV energy band.)
28 see http://cxc.harvard.edu/ciao/why/dither.html
suspected of being significant contributors to the ASCA
counts detected in the AGPS. (All these faint sources are
included in Table 1.) In order to determine the detection
significance of these sources, we independently calculated
the probability of a false detection (Pfd) for each source based
on the Poisson statistics. We expect there to be ∼ 100000
trials in a 30 radius ACIS CCD field-of-view if a detection
cell size of a 100 radius circle is assumed with 2D Nyquist
sampling (Weisskopf et al. 2007). (A generic detection
cell size of 100 for this detection significance calculation
was suggested by Weisskopf et al. (2007) since the CIAO
source detection algorithms usually use a detection cell size
of between 40 − 80% of the PSF at a given energy.29 ) Pfd
= 10−5 implies that there is one false source in the 30 radius
ACIS Chandra field. The probability of a false detection
was calculated for each source (see footnote 13 in Kashyap
et al. 2010). Only 11 sources (out of 253) have a Pfd > 10−5
but all have Pfd < 7 × 10−4 . Several of these sources also
have a likely optical and/or infrared counterpart, increasing
the significance of these detections. As this technique for
calculating source significance is highly theoretical (e.g. the
effective detection cell size of ACIS is likely to be slightly
smaller than the 100 radius circles), without any consideration
for possible counterparts, we will include these 11 marginally
significant sources in Table 1 (denoted by a * symbol in the
first column).
Several of the sources detected in these observations have also
been listed in the Chandra Source Catalog (CSC; Evans et al.
2010). We assume that a CSC source and a ChIcAGO source
are the same if the separation between their two positions
is less than the quadratic sum of their 95% error radii plus
a constant term of 0.00 7, which accounts for the 95% absolute astrometry error of Chandra assuming the errors follow a
Gaussian distribution30 (see Equation (6) of Hong et al. 2005).
We have conducted the same comparison with the fifth public release of the Second XMM-Newton Serendipitous Source
Catalogue (2XMMi-DR3; Watson et al. 2009)31 . The CSC
and 2XMMi-DR3 names that correspond to any ChIcAGO
sources are listed in Table 1. Further analysis of the XMM
observations will be conducted in future work.
The purpose of the ChIcAGO survey is to study those Xray sources detected in the ChIcAGO Chandra observations
that fall within the flux range of the AGPS sources (Fx ∼
10−13 to 10−12 erg cm−2 s−1 ). In 62 out of the 93 AGPS sources
observed with Chandra, ChIcAGO MAP found 74 sources
with > 20 X-ray counts that fall within the investigated 30
field-of-view that is centered on the AGPS positions. For the
purposes of this study we will focus on these 74 ChIcAGO
sources, listed in Table 2, as they are approximately within
the original AGPS flux range. The detailed analysis of those
179 ChIcAGO sources with < 20 counts will be deferred to
future work. There were 6 AGPS sources where no ChIcAGO
source was detected by Chandra: AX J165951–4209, AX
J175331–2538, AX J180816–2021, AX J183607–0756, AX
J185905+0333, and AX J191046+0917. At least three of
these AGPS sources, AX J180816–2021, AX J185905+0333,
and AX J191046+0917, may be transient given how bright
29
See the CIAO detect manual http://cxc.harvard.edu/ciao/download/doc/detect_manual/
The Chandra astrometric error is included in this calculation as the
source positions listed in the CSC can be obtained from more than one
dataset.
31 http://xmmssc-www.star.le.ac.uk/Catalogue/2XMMi-DR3/
30
T HE C H I C AGO S URVEY
they were in the original ASCA detections (Sugizaki et al.
2001). The remaining 25 AGPS fields observed with Chandra only have faint sources with < 20 X-ray counts. There are
also 6 AGPS sources, AX J144519–5949, AX J151005–5824,
AX J154905–5420, AX J194310+2318, AX J194332+2323,
and AX J195006+2628, where multiple ChIcAGO sources
detected in each region (with . 30 X-ray counts) sum to & 60
counts, which are close to the number of X-ray counts that
were expected to be detected with Chandra from each AGPS
source (see Section 2.1). Many of the ChIcAGO sources in
these field also have optical and/or infrared counterparts and
may therefore be members of star clusters (see Section 4.1 for
further discussions).
0
The contribution of X-ray emission beyond the 3 search radius was also investigated using wavdetect to identify all
the point sources with > 20 X-ray counts in the Chandra observations that lie between 30 − 50 from the original AGPS position. Only 14 X-ray point sources were found in the 30 − 50
annulus surrounding 11 AGPS sources, which demonstrates
that the 30 search radius used by ChIcAGO MAP is reasonable
and has likely allowed us to identify the majority of ChIcAGO
sources. These 14 X-ray point sources are further discussed in
Appendix B where we explore the likelihood of whether they
could be associated with their nearby AGPS source.
3.2. Quantile Analysis and Spectral Modeling Results
Quantile analysis and spectral modeling using Cash statistics were both techniques used to infer the most likely absorbed power-law and absorbed thermal bremsstrahlung spectrum of the bright ChIcAGO source detected by ACIS-S.32
The spectral parameters and the absorbed and unabsorbed Xray fluxes for an absorbed power law and absorbed thermal
bremsstrahlung model are listed in Tables 3 and 4, respectively. There are also six HRC-I detected ChIcAGO sources
with > 20 counts (ChI J144042–6001_1, ChI J153818–
5541_1, ChI J163252–4746_2, ChI J163751–4656_1, ChI
J165420–4337_1, and ChI J172642–3540_1) that are not included in Tables 3 and 4 as their X-ray observations do not
contain any spectral information. The possible counterparts
to these six sources are, however, explored in detail in Section 3.3.
There is no measure of goodness for the quantile analysis derived absorbed power-law and absorbed bremsstrahlung spectral parameters listed for the ChIcAGO sources in Tables 3
and 4. Instead a spectral interpolation is classified as unreasonable if the resulting parameters are outside −2 < Γ <
4 for a power-law model and 0.1 < kT < 10 keV for a
bremsstrahlung model. These parameter limits can allow for
the grouping of the ChIcAGO sources into existing categories
that are based on the physical understanding of X-ray sources
that emit in the Chandra energy range (0.3 − 8 keV). While
these selection criteria explicitly excludes the identification
of new types of X-ray sources with unusual spectra, such an
investigation is beyond the scope of this work. In all cases if
one of the quantile analysis spectral interpolations was disregarded for a given ChIcAGO source, the other is reasonable
when considering the above criteria.
As a way to further explore the goodness of the spectral interpolations, the CIAO spectral fitting tool Sherpa was used
32 ChIcAGO sources with > 20 X-ray counts for quantile analysis and
> 50 X-ray counts for spectral modeling.
11
to fit the X-ray spectrum of each ChIcAGO source with spectral parameters derived from quantile analysis in Tables 3 and
4. The χ2red was calculated for each ChIcAGO source where
> 40 X-ray counts was detected with ACIS-S. In many cases
we found χ2red < 1, which is not unexpected given the low
number of X-ray counts detected, indicating that any reasonable model is a decent fit. However, there are also a few cases
where χ2red > 2 indicating that the spectral parameters do not
adequately describe the spectrum. The values of χ2red corresponding to the quantile interpolated spectral parameters are
included in Tables 3 and 4.
The parameters and fluxes resulting from the absorbed power
law and absorbed thermal bremsstrahlung spectral modeling
of the ChIcAGO sources have also been included in Tables 3
and 4 so that they can be directly compared to the quantile
analysis results. Best fit absorbed power law parameters were
obtained for all the ACIS-S detected ChIcAGO sources with
> 50 X-ray counts (see Table 3). However, there were several
cases where the absorbed thermal bremsstrahlung fitting was
unsuccessful as the Sherpa modeling algorithm hit the hard
maximum limit on the kT parameter (10 keV). These unsuccessful fits were not included in Table 4.
All of the parameters and absorbed fluxes derived from the
Cash statistics spectral fitting agree within 3σ of those derived from the quantile analysis spectral interpolation, the
majority of which agree within the 1σ errors. The only exception is the kT parameter value for ChI J171910–3652_2.
However, the unabsorbed fluxes were far less agreeable between the two techniques as there were several ChIcAGO
sources for which this value differed by > 3σ. These include ChI J183356–0822_2 and ChI J184738–0156_1 from
the power law spectral analysis and ChI J144547–5931_1,
ChI J144701–5919_1, ChI J165646–4239_1, ChI J171910–
3652_2, ChI J172050–3710_1, and ChI J185608+0218_1
from the bremsstrahlung spectral analysis. Both these techniques therefore appear to be successful in constraining the
spectral parameters and absorbed fluxes for each of the investigated ChIcAGO sources but less successful in constraining
the unabsorbed fluxes. It should also be noted that the majority of the reduced Cash statistics from the spectral modeling
were systematically higher than the corresponding χ2red derived from the spectral parameters interpolated through quantile analysis.
3.3. Infrared and Optical Counterparts
Infrared and optical follow-up were primarily performed on
those ChIcAGO sources with > 20 X-ray counts (see Table 2).
In order to determine which optical and infrared sources are
counterparts to ChIcAGO sources, we used a similar technique to that described by Zhao et al. (2005), using their
Equation (11). If the separation between a ChIcAGO source’s
wavdetect position and its possible counterpart is less than
the quadratic sum of their 3σ position errors and the 3σ Chandra pointing error33 , then the X-ray and optical (or infrared)
sources are likely to be associated. The 1σ position errors for
all sources in 2MASS PSC and the GLIMPSE34 catalogs are
0.00 1 (Skrutskie et al. 2006) and 0.00 3, respectively. USNO B
has an astrometric accuracy of < 0.00 25 (Monet et al. 2003).
33
34
http://cxc.harvard.edu/cal/ASPECT/celmon/
See GLIMPSE documents http://www.astro.wisc.edu/sirtf/docs.html
12
We have assumed that the error distributions of the Chandra
observations, Chandra pointing, and USNO B Catalog are all
Gaussian for the purposes of identifying possible counterparts
to the ChIcAGO sources. While this assumption is not necessarily correct in every case, the full examination required to
obtain the Gaussian errors would involve a very complicated
approach. However, other Chandra Galactic plane X-ray surveys that search for multi-wavelength counterparts assuming
Gaussian errors for cross-correlation purposes have had successful results (e.g. ChaMPlane; Zhao et al. 2005). Based on
these results we feel that Gaussian errors are an acceptable
assumption for the purpose of identifying optical and infrared
counterparts to the ChIcAGO sources.
The infrared properties, such as the names and magnitudes of
any likely 2MASS or GLIMPSE counterparts, together with
the NIR magnitudes (J, H, and K) obtained from Magellan
PANIC observations, are listed in Table 2 along with the date
of each observation. We assume that those ChIcAGO sources
with no listed 2MASS (or PANIC) counterpart have 2MASS
PSC limiting magnitudes J > 15.8, H > 15.1, and K > 14.3
(Skrutskie et al. 2006). In Table 5, optical magnitudes have
also been provided for those 44 ChIcAGO sources with > 20
X-ray counts that have optical counterparts in the USNO B1
Catalog or in one of the IMACS or MagIC Magellan observations. Two other ChIcAGO sources (ChI J170017–4220_1
and ChI J181213–1842_7) with magnitude limits obtained
with either IMACS or MagIC are also included in Table 5.
Of the 74 ChIcAGO sources with > 20 X-ray counts listed
in Table 2, 59 have a NIR counterpart, 44 of which are
2MASS sources and 15 of which were detected in PANIC
observations. Looking into the mid-infrared wavelength
bands, we find that 41 of these 2MASS sources and 3 of
the PANIC sources also have GLIMPSE counterparts. NIR
magnitude limits were obtained for 4 other PANIC-observed
ChIcAGO sources, since any possible counterparts were too
faint to be detected or, in the case of ChI J181116–1828_2
and ChI J185643+0220_2, the counterpart appeared to be
blended. (ChI J181116–1828_2 does, however, have a unique
GLIMPSE counterpart.) If we include ChI J181116–1828_2
and ChI J185643+0220_2, for which we have detected a
counterpart but the magnitudes are only an upper limit due to
blending, then 89% of our PANIC observations of ChIcAGO
sources have yielded a detection in one of more of the J, H,
or K filter bands. There are also a few ChIcAGO sources
where the 2MASS counterpart magnitudes are listed as 95%
confidence upper limits due to a non-detection or inconsistent
deblending. We were therefore able to use PANIC to obtain
more accurate magnitudes for 4 ChIcAGO sources for which
have limited 2MASS magnitude information in one or more
bands. (These 4 ChIcAGO sources can be identified as those
with three letters listed in the “Data” column of Table 2.)
All of the 46 ChIcAGO sources listed in Table 5 (44
ChIcAGO sources with optical counterparts and 2 with limiting magnitudes obtained with Magellan instruments) have
NIR counterparts detected with either 2MASS or PANIC. Of
the 44 with optical counterparts, 41 have USNO B1 counterparts, for 4 of which extra magnitude measurements were
obtained with one of the two Magellan optical imagers. A
further 3 ChIcAGO sources, uncataloged in USNO B1, were
also detected in the optical with these Magellan instruments.
Of the 74 ChIcAGO sources with > 20 X-ray counts, 14 do
not have a detected optical, NIR or IR counterpart.
We conducted an experiment similar to that outlined in Kaplan et al. (2004) to quantify the probability that the optical
and infrared survey counterparts quoted in Tables 2 and 5,
are a random chance association with the > 20 X-ray count
ChIcAGO source of which they are coincident. We searched
for all 2MASS, GLIMPSE and USNO B1 sources brighter
than the possible counterpart listed in Tables 2 and 5 within
100 of each ChIcAGO source position. (We only searched
for survey sources that have a brighter Ks , 3.6µm, and second epoch R band magnitude for the 2MASS, GLIMPSE and
USNO B1 surveys, respectively.) We then used the resulting
statistics to determine the number of survey sources brighter
than the listed counterpart that are likely to be detected within
a region the same size as the ChIcAGO source’s 95% position
error circle. We did this for each ChIcAGO source individually as the density of sources can vary dramatically across
the Galactic plane. In most cases the resulting chance of a
random association is very low (< 0.01). Those ChIcAGO
sources that have a random chance of association > 0.01 in
either 2MASS or GLIMPSE are listed in Table 6. For each
ChIcAGO source the chance of a random association with a
USNO B1 is < 0.01.
We refer to the ChIcAGO sources that have < 20 counts
as “secondary” sources. In Table 7 we list the names of
any USNO B1, 2MASS and GLIMPSE sources that appear
to be coincident with a secondary ChIcAGO source based
on our position agreement criteria outlined in Section 2.4.1.
This Table also includes the offset in arcseconds between
the secondary ChIcAGO source’s wavdetect position and
the position of the coincident survey source. (Only those
secondary ChIcAGO sources that have a coincident survey
source have been included in Table 7.) A summary of the
fraction of ChIcAGO sources with a coincident source in the
2MASS, GLIMPSE and USNO B1 catalogs, can be found in
Table 8. This Table includes the fraction of the total number
of ChIcAGO sources, as well the fraction of just the > 20 Xray count ChIcAGO sources, with a coincident survey source.
(Note that we assume the coincident survey sources to the
> 20 X-ray count ChIcAGO sources are counterparts based
on the very low chance of random associations as demonstrated by Table 6.)
3.4. Radio Counterparts
As mentioned in Section 2.4.2, the position of each ChIcAGO
source (above and below 20 X-ray counts) was visually inspected for any possibly associated radio emission in the
MGPS, MAGPIS, VGPS and the 90cm Multi-configuration
Very Large Array Survey of the Galactic Plane. The results of
this inspection are listed in Table 9. ChIcAGO source position
comparisons were also made with the Green (2009) catalog of
Galactic supernova remnants. Any possibly counterparts that
are known objects, such as supernova remnants (SNRs), H II
regions, infrared dark clouds (IRDCs; Peretto & Fuller 2009),
colliding-wind binaries (CWBs) or massive stars, are listed in
Table 9 under “type”. However, if the radio sources are uncataloged, they have instead been flagged as being possibly compact, diffuse, or arc/shell structured diffuse emission. Two
ChIcAGO sources, ChI J181116–1828_5 and ChI J184741–
0219_3, appear to be previously unidentified AGN as their
coincident radio sources show core-lobe morphologies in the
MAGPIS 1.4 GHz survey images.
Each of the ChIcAGO sources with a possible radio associ-
T HE C H I C AGO S URVEY
ation is then listed in Table 9 as being either coincident to,
adjacent to, or on the limb of the radio source (such as on the
limb of a SNR, diffuse emission or H II region). If a ChIcAGO
source is listed as either coincident or on the limb of a SNR
then this means it is within the extent of the SNR based on the
SNR’s size quoted in the Green (2009) catalog. In the cases
of the two candidate AGN, these ChIcAGO sources appear to
be directly coincident with the core of the AGN. The name of
each radio source and the corresponding reference are listed
in Table 9.
The 10 ChIcAGO sources observed with the ATCA are also
included in Table 9. The ATCA-detected compact radio
counterparts to both ChI J144701–5919_1 and ChI J163252–
4746_2, aided in their identification as X-ray emitting massive
stars or CWBs (see Anderson et al. 2011). No radio counterparts were detected for the other 8 ChIcAGO sources observed with the ATCA.
In summary, Table 9 shows there to be 16 ChIcAGO sources,
from the Chandra observations of 8 different AGPS source
regions, that are coincident, or on the limb, of 9 SNRs. There
are 54 ChIcAGO sources, from 7 different AGPS source regions, that fall within the extent of 6 H II regions. There are
also 4 massive stars, all of which are confirmed or candidate
CWBs (see Anderson et al. 2011; Motch et al. 2010), with
radio counterparts. Only two ChIcAGO sources, both toward
the same single AGPS target, are coincident with an IRDC.
Several ChIcAGO sources also fall within regions of uncataloged extended radio emission. These include 15 ChIcAGO
sources, from 5 different AGPS source regions, falling within
the extent of 5 regions of diffuse radio emission. Of these 15
ChIcAGO sources, there are 6 (from 3 different AGPS source
regions) that are coincident with uncataloged diffuse emission
with an arc or shell structure. Excluding the two AGN candidates, there is only one other ChIcAGO source coincident
with an unidentified compact radio source.
There are 74 ChIcAGO sources (14 sources with > 20 X-ray
counts and 60 with < 20 X-ray counts), out of the 253 detected, with no optical or infrared counterparts, making them
possible compact object candidates and therefore potentially
detectable in the radio. We therefore searched for any possible
pulsar counterparts in the Australia Telescope National Facility Pulsar Catalogue (Version 1.4435 Manchester et al. 2005)
but no known pulsars exist within 0.0 6 of the wavdetect position of any of the 74 sources.
4. DISCUSSION
4.1. Unidentified ChIcAGO Sources with Radio Counterparts
Table 9 lists 16 ChIcAGO sources that fall within the extent
of 9 SNRs. X-ray point sources within SNRs could be associated compact objects. Identification of an optical or infrared
counterpart discounts such a possibility, since the optical/IR
counterparts to neutron stars and other compact objects are
expected to be very faint (for the details on this approach see
Kaplan et al. 2004). Those SNR coincident ChIcAGO sources
with a random chance of association > 0.01 in the USNO B1
and GLIMPSE catalogs are listed in Table 10. (The chance
of a random association between one of these 16 ChIcAGO
sources and a 2MASS catalog source is < 0.01.)
35
http://www.atnf.csiro.au/research/pulsar/psrcat
13
Of the 16 ChIcAGO sources inside SNRs, only 5 have no optical or infrared counterparts. These 5 X-ray sources are all
very faint, with < 8 X-ray counts detected for each in the
ChIcAGO Chandra observations. These are ChI J145732–
5901_2 in SNR G318.2+0.1 (Whiteoak & Green 1996),
ChI J182435–1311_2,3,4 in SNR G18.1–0.1 (Helfand et al.
2006; Brogan et al. 2006) and ChI J184447–0305_1 in SNR
G29.3667+0.1000 (Helfand et al. 2006). Bocchino et al.
(2001) has already reported on three X-ray sources within
SNR G318.2+0.1 but not at the position of ChI J145732–
5901_2. Both SNR G18.1–0.1 and SNR G29.3667+0.1000
are newly discovered SNRs so little X-ray analysis has been
done on these objects. Further investigation is required to determine if any of these 5 ChIcAGO sources are compact objects and if they are associated with the surrounding SNRs.
There are 54 ChIcAGO sources coincident with 6 different H
II regions that were detected in the ChIcAGO Chandra observations of 7 AGPS sources (see Table 9). Based on the results
from X-ray observations of other H II regions (for example
see Broos et al. 2007) it is possible that many of these 54
ChIcAGO sources could be pre-main sequence (PMS) stars,
massive OB and WR stars, and CWBs. Simpson & Cotera
(2004) also found optically obscured star clusters in 2MASS
images within 10 of 3 of these AGPS sources; AX J144519–
5949, AX J151005–5824, and AX J162208–5005, which supports a H II region and young and massive star interpretation
for these ASCA sources. Of these 54 ChIcAGO sources, 43
have optical and/or infrared counterparts supporting a possible stellar origin (see Tables 2, 5 and 7). In most cases
the chance of random association with a field source is low
(< 0.01). Those H II region coincident ChIcAGO sources for
which the chance of random association with a 2MASS or
GLIMPSE source is > 0.01 are listed in Table 11.
The possible nature of these H II region coincident ChIcAGO
sources could be further investigated by comparing their luminosities to those of PMS stars, massive OB and WR stars,
and CWBs. A spectral analysis of the 54 ChIcAGO sources
is extremely difficult given that they all have ≤ 32 X-ray
counts. However, the primary goal is to obtain a wide-band
flux that can then be converted into a luminosity. Quantile
analysis was therefore performed to obtain absorbed MeweKaastra-Liedahl (Mekal; Mewe et al. 1985, 1986; Kaastra
1992; Liedahl et al. 1995) spectral interpolations of all the H
II region coincident ChIcAGO sources with ≥ 5 X-ray counts.
A Mekal model was chosen as thin thermal plasma emission is
expected from hot X-ray emitting stars (for example see Wolk
et al. 2005; Sana et al. 2006). The absorbed Mekal spectral interpolations can be found in Table 11.
The luminosity of these ChIcAGO sources were calculated
using kinematic distance estimates to the H II regions of
which they are coincident. Kinematic distances calculated
by Russeil (2003) were used to calculate luminosities for
the ChIcAGO sources coincident with G320.3–0.3, G333.6–
0.2, and G59.5–0.2. (Note that there is a more distant kinematic distance estimate of 6.3 kpc to G59.5–0.2 calculated by
Kuchar & Bania (1994) but we have decided to use the more
recent estimate from Russeil (2003).) The kinematic distances used in the luminosity calculations for G326.96+0.03
and G62.9+0.1 were obtained from McClure-Griffiths et al.
(2001) and Fich & Blitz (1984), respectively. The kinematic
distance to the massive young stellar object G316.8112–
00.0566 (Busfield et al. 2006), likely embedded within GAL
14
316.8–00.1, was used in the luminosity calculations for those
ChIcAGO sources coincident with this H II region. (The distance from Busfield et al. (2006) agrees reasonably well with
the near kinematic distance to GAL 316.8–00.1 calculated by
Caswell & Haynes (1987) when revised for a modern Galactic center distance of 8.5 kpc.) Table 11 lists the kinematic
distance and corresponding absorbed and unabsorbed luminosities calculated for each H II region coincident ChIcAGO
source.
The range of absorbed luminosities calculated for all the
ChIcAGO sources coincident with the 6 H II regions span
the range 30.6 ergs−1 < Log Lx,abs < 32.4 ergs−1 (0.3 − 8
keV). This absorbed luminosity range is similar to that observed from the H II region M17 (29.3 ergs−1 < Log Lx,abs <
32.8 ergs−1 (0.5 − 8 keV); Broos et al. 2007). With the exception of ChI J151005–5824_8, the H II region coincident
ChIcAGO sources in Table 11 have unabsorbed luminosities
between Lx,unab ∼ 1031 to 1035 erg s−1 . The unabsorbed luminosities of these ChIcAGO sources cover the ranges of
what has been observed from flaring PMS stars (Lx,unab ∼
1030 to 1033 erg s−1 ; Favata et al. 2005; Wolk et al. 2005), single and binary massive O type stars (Lx,unab ∼ 1031 to 1033 erg
s−1 ; Oskinova 2005; Sana et al. 2006), WR stars (Lx,unab ∼
1031 to 1034 erg s−1 ; Oskinova 2005; Mauerhan et al. 2010),
and CWBs (Lx,unab ∼ 1032 to 1034 erg s−1 ; Oskinova 2005;
Mauerhan et al. 2010). In fact, we were able to identify
ChI J194310+2318_5, which is within G59.5–0.2, as the
O7V((f)) type star HD 344784 (Walborn 1973) using the SIMBAD Astronomical Database. It is therefore likely that the
AGPS sources AX J144519–5949, AX J151005–5824, AX
J154905–5420, AX J162208–5005, AX J194310+2318, AX
J194332+2323, and AX J195006+2628 are young and massive stars within H II regions. Deeper X-ray, radio and IR
observations are required to determine the precise nature of
the individual ChIcAGO sources.
4.2. Unidentified ChIcAGO Sources with Infrared
Counterparts
The X-ray and infrared population statistics performed in
this section are just conducted using those ChIcAGO sources
with > 20 X-ray counts, therefore concentrating on the persistent populations that fall within the AGPS flux range
(Fx ∼ 10−13 to 10−11 erg cm−2 s−1 ). However, discarding the
ChIcAGO sources with < 20 X-ray counts limits our analysis as we are excluding the populations of sources that exhibit
long term variability or transient behavior. Sources with < 20
X-ray counts will need to be investigated in future work using
archival X-ray observations at different epochs.
4.2.1. X-ray and Infrared Populations Statistics
Using the X-ray and infrared properties of the unidentified
ChIcAGO sources, it is possible to classify some of the
sources detected in the AGPS into possible populations. We
chose to focus on the IR counterparts as this waveband is less
affected by interstellar extinction when compared to the optical band. This group of sources therefore makes up a larger
subset of the unidentified ChIcAGO sources than those with
optical counterparts (see Section 3.3). For those unidentified
ChIcAGO sources observed with the Chandra HRC instrument (for which there is no spectral information), we gen-
erated fake spectra, using XSpec and the CIAO spectral fitting tool Sherpa. These spectra are based on the absorbed
power-law fits reported in Sugizaki et al. (2001), allowing the
absorbed X-ray flux and median energy (E50 ) of the unidentified ChIcAGO source in question to be calculated. These
values are used in the statistical plots described below.
To help identify possible distinct populations in the statistical plots, we have also included both archival sources (those
AGPS source identified by Sugizaki et al. 2001, or in the literature and so were not observed with Chandra as part of
the ChIcAGO survey) and the previously identified ChIcAGO
sources (for example those investigated by Anderson et al.
2011, 2012). Fake spectra were generated using Sherpa and
XSpec for these archival sources, using spectral fits in the
literature, to determine their absorbed X-ray fluxes and E50
values for the energy ranges investigated. All archival AGPS
sources are summarized and tabulated in Section 4.5 (see Table 12) and are individually described in Appendix A.
The identified sources were divided into the following categories: AGN, CVs, CWBs, HMXBs, magnetars, massive
stars and stars. The “AGN” category includes ChI J184741–
0219_3, which we identified by positional comparison with
MAGPIS radio data (for the radio identification and further
details on this source see Sections 3.4 and 4.3.15, respectively). The “CWB” category includes AX J163252-4746
and AX J184738-0156, which were identified in Anderson
et al. (2011, listed as ChI J163252–4746_2 and ChI J184738–
0156_1 in Table 1, respectively), and AX J183116–1008
and AX J183206–0938, which were identified in the XGPS
(Motch et al. 2010, listed as ChI J183116-1008_1 and ChI
J183206-0938_1 in Table 1, respectively). The “HMXB”
category includes the archival AGPS sources that are supergiant HMXBs (McClintock & Remillard 2006), supergiant
fast X-ray transients (SFXTs; Sguera et al. 2006), and SyXBs
(Masetti et al. 2007). The infrared and X-ray fluxes from
magnetars are variable and correlated (Durant & van Kerkwijk 2005) so the fluxes we used in the “magnetar” category are from infrared and X-ray observations that occurred
close together in time. PSR J1622–4950, which was determined through the ChIcAGO Chandra observation to be
the main contributor to AX J162246–4946 has also been included as an identified magnetar (see Anderson et al. 2012,
and Section 4.3.6 for further details). The sources included
in the “massive star” category are massive stars that are WolfRayet (WR), luminous blue variable (LBV) stars, and massive
O-type stars, which emit X-rays through instability-driven
wind-shocks (Lucy & White 1980; Lucy 1982) and possibly through colliding-winds in a CWB. These include AX
J144547-5931 and AX J144701-5919, which were identified
by Anderson et al. (2011, listed as ChI J144547-5931_1 and
ChI J144701-5919_1 in Table 1, respectively). All other nondegenerate stars are in the “star” category, and most likely
correspond to active stellar coronae or PMS stars.
We first investigated the relationship between the X-ray and
infrared flux of the ChIcAGO sources by comparing these
properties to those of known stars and AGN. Figure 5 of
Gelfand & Gaensler (2007) shows the X-ray versus Ks -band
flux of sources from the Chandra Orion Ultradeep Project
(COUP; Getman et al. 2005) and XBootes Survey (Jannuzi
et al. 2004; Kenter et al. 2005), which are stars (predominantly in the PMS) and AGN, respectively. In Figure 7 we
create a similar plot that includes the unidentified ChIcAGO
T HE C H I C AGO S URVEY
sources (U ChIcAGO; red data points) along with the COUP
stars (blue crosses) and the XBootes Survey AGN (magenta
diamonds) (for further details on the data from these surveys
see Gelfand & Gaensler 2007, and references therein). The
X-ray flux (Fx,2−7keV ) is over the 2.0 − 7.0 keV energy range
and the Ks -band flux (FKs = λFλ,Ks ) is derived from Fλ,Ks
(erg cm−2 s−1 µm−1 ) where the effective wavelength is λ =
2.159 µm. The archival sources and the identified ChIcAGO
sources with K-band counterparts have also been included in
Figure 7 in order to further distinguish between possible Xray populations.
Two groups and two outliers are apparent in Figure 7 among
the unidentified ChIcAGO sources: group 1, those coincident
with the COUP stars, and group 2 that sits to the right of the
AGN detected in the XBootes survey. The two outliers are
ChI J154557-5443_3, on the very left of this Figure with a
hard X-ray flux limit of Fx,2−7keV . 3 × 10−19 erg cm−2 s−1 ,36
and the source on the bottom right, ChI J153818-5541_1, with
an X-ray flux of Fx,2−7keV ∼ 1 × 10−11 erg cm−2 s−1 , located
near the identified magnetars.
Group 1 is distributed similarly to the COUP stars, following a “track” indicating an increase in K-band flux with X-ray
flux. This comparison demonstrates that a large number of the
ChIcAGO stellar population could be PMS stars. While the
overall Galactic X-ray population is dominated by field stars,
we would expect that the ChIcAGO survey (and the AGPS)
is bias towards PMS stars as such objects are brighter and
harder X-ray emitters (for example see Wolk et al. 2005). The
identified ChIcAGO and archival sources that have been categorized as massive stars (light pink dots) and CWBs (green
data points) congregate near the top right of group 1, beyond
most of the COUP stars. These massive stars and CWBs are
composed of massive late-type WR stars in the nitrogen sequence that are hydrogen rich (WNH: Smith et al. 2008), or
their massive O star progenitors (Of: Crowther et al. 1995), all
of which are expected to be bright in the infrared and potentially harder in X-rays than other types of X-ray emitting stars
(yellow data points). (See Anderson et al. 2011, for further details on these WR and massive O stars.) It is therefore possible that the unidentified ChIcAGO sources located near these
massive stars and CWBs in Figure 7 could be similar objects.
It should also be noted that the identified AGPS HMXBs sit to
the right of group 1, with no unidentified ChIcAGO sources
near their positions to draw comparison with.
Group 2 sits at a similar Ks -band flux but higher X-ray flux
than the AGN from the XBootes survey. The identified
ChIcAGO and archival AGN are coincident with the unidentified ChIcAGO sources in group 2, indicating that at least part
of this group could also be AGN. Such AGN would have to
be very X-ray bright in order to be detected through the high
foreground column density in the Galactic plane. The identified archival CVs sit adjacent to group 2, at a slightly higher
X-ray flux, indicating another possible population identification.
The unidentified ChIcAGO source ChI J154557-5443_3, has
a similar K-band flux to the COUP stars but has an extremely
faint hard X-ray flux. No identified ChIcAGO or archival
sources are located near ChI J154557-5443_3 in Figure 7 that
suggest a clue to its nature. ChI J154557-5443_3 is discussed
36 The majority of X-ray counts that Chandra detected from ChI J1545575443_3 were soft (< 2 keV). This hard flux is therefore an upper-limit.
15
further in Section 4.3.4.
The unidentified ChIcAGO source that sits at the bottom right
of Figure 7, ChI J153818-5541_1, is very faint in the nearinfrared but bright in high energy X-rays. It is therefore
very similar in both X-ray and Ks -band flux to the identified
archival magnetars, suggesting a similar identification that
warrants further investigation. ChI J153818-5541_1 is further
discussed in Section 4.3.3.
In order to further identify the possible populations that make
up the above described groups, we created a statistical plot
that also takes into account the hardness of each of the unidentified ChIcAGO sources. Figure 8 plots the X-ray-to-Ks -band
flux ratio (Fx,0.3−8.0keV /FKs ) versus the median energy (E50
keV), in the 0.3 − 8.0 keV energy band, of each unidentified ChIcAGO source (“U ChIcAGO;” red data points). We
further separated the ChIcAGO sources into the categories
“low”, “medium” and “high”, based on their ACIS-S and
HRC-I X-ray count rates, using symbol sizes to distinguish
these categories. The smallest data points (low) have count
rates < 15 counts s−1 , the medium sized data points (medium)
have count rates between 15 and 40 counts s−1 , and the largest
data points (high) have count rates > 40 counts s−1 . The identified ChIcAGO and archival sources, also divided into categories based on the X-ray count-rate expected from a Chandra
ACIS-S observation, have also been included in Figure 8. As
the X-ray fluxes and median energy errors are fundamentally
based on the number of X-ray counts detected in the Chandra observations, we show two representative error bars for
the low count ChIcAGO sources (20 − 60 counts) and the high
count ChIcAGO sources (80 − 120 counts). The error associated with the Ks -band flux is greater for PANIC magnitudes
than for 2MASS magnitudes. We therefore adopt the PANIC
Ks -band flux errors so that the vertical error bars represent the
maximum possible error in the Fx /FKs ratio for low- and highcount unidentified ChIcAGO sources.
In Figure 8, group 1 plus the source ChI J154557-5443_3
from Figure 7 have flux ratios Fx /FKs < 0.1 but have a wide
range of median energies. Group 2 is harder than group 1,
with E50 > 1.5 keV but with a flux ratio 0.1 < Fx /FKs <
20. The unidentified ChIcAGO source ChI J153818-5541_1,
from Figure 7 is quite hard (E50 > 3 keV), with Fx /FKs ≈ 300.
Using Figure 7 as a guide, as well as the relative positions
between the unidentified ChIcAGO sources and the identified
ChIcAGO and archival sources in Figure 8, we divided the
groups and isolated sources from Figure 7 into six different
population regions. These regions are marked by dashed lines
and labeled with Roman numerals in Figure 8. The region
boundaries in this plot are based on the observed X-ray properties and Ks band flux. If these values were extinction and
absorption corrected, both the Fx /FKs and E50 region boundaries would lower.
Region i (E50 < 1.5 keV and Fx /FKs < 0.1) in Figure 8 contains unidentified ChIcAGO sources with low, medium and
high count rates. The majority of the low count rate unidentified ChIcAGO sources included in this Figure fall into this
region. These low count rate sources could be either very
nearby objects that were only detected due to their close proximity to the Solar System or they are simply a more distant
version of the medium and high count rate sources in Region
i. All the unidentified ChIcAGO sources in this region are unlikely to be extragalactic given their softer X-ray spectra and
16
Figure 7. Observed Ks -band flux (FKs ) vs absorbed 2 − 7 keV X-ray flux (Fx,2−7keV ) of unidentified ChIcAGO sources (“U ChIcAGO:” red points) and identified
ChIcAGO and archival sources. Triangular data points represent those sources that only have upper limits on their Ks -band fluxes. The Chandra Orion Ultradeep
Project sources (blue crosses) and the XBootes Survey sources (magenta diamonds), which are predominantly PMS stars and background AGN, respectively, are
also included. The lone red data point on the far left of the diagram (ChI J154557–5443_3) should be treated as a X-ray flux upper limit as Chandra detected
very few hard X-ray counts (> 2 keV) from this source. This plot is based upon Figure 5 of Gelfand & Gaensler (2007).
Figure 8. Observed X-ray-to-Ks -band flux ratio (Fx,0.3−8keV /FKs ) vs median energy (E50 keV) of unidentified ChIcAGO sources and the identified ChIcAGO
and AGPS sources. The different sizes of data points represent whether a given source has a low count-rate (L as listed in the legend), medium count-rate (M) or
a high count-rate (H). The unidentified ChIcAGO sources (“U ChIcAGO”) are represented by red data points and the identified ChIcAGO and archival sources
are in other colors. The triangles represent those sources that only have upper limits on their Ks -band fluxes, implying lower limits on their Fx /FKs ratios. The
representative error bars demonstrate the sizes of errors expected from a 20 − 60 count X-ray source or a 80 − 120 count X-ray source. This plot has been divided
into 6 regions, indicated by the dashed lines and Roman numerals, in order to further explore the source populations (see Section 4.2).
T HE C H I C AGO S URVEY
bright Ks -band counterparts compared to the XBootes AGN
in Figure 7. Within this region are three of the archival X-ray
stars (yellow data points), of which there is an RS CVn star, a
PMS star and a multiple system. The unidentified ChIcAGO
sources in Region i are therefore likely to be soft X-ray stars
with active stellar coronae or PMS stars, similar to the three
archival stars, but at a variety of distances in the Galaxy.
The sources in Region ii (E50 > 1.5 keV and Fx /FKs < 0.1)
of Figure 8 have similar Fx /FKs ratios, but slightly harder Xray emission, to those in Region i. This region also has fewer
unidentified ChIcAGO sources than Region i, implying that
it may contain a slightly rarer X-ray source population. The
majority of the unidentified ChIcAGO sources in Region ii
have low or medium count-rates, with only one in the high
count rate category. The identified ChIcAGO and archival
sources in this region are CWBs (green data points) and massive stars (pink dots), all of which sit at the top of the stellar
track in Figure 7. We defined E50 > 1.5 keV as the lower
energy cutoff of Region ii by looking at the closest unidentified ChIcAGO sources to the CWBs and massive stars in Figure 7. The CWBs and massive stars are WNH and Of stars,
which produce X-rays through instability-driven wind-shocks
but can also, in the case of CWBs, produce hard X-rays due
to colliding-winds (for example see Anderson et al. 2011).
It is therefore likely that many of the unidentified ChIcAGO
sources in Region ii are WR and Of stars, some of which may
also be CWBs.
Region iii (E50 > 4.0 keV and 1 × 10−3 < Fx /FKs < 20) in
Figure 8 encompasses the archival HMXBs (grey dots) and
the archival and identified ChIcAGO AGN (cyan dots). The
only two unidentified ChIcAGO sources in this region are
ChI J170017-4220_1 (high) and ChI J172550-3533_1 (low),
and are therefore quite hard X-ray sources, making HMXB or
AGN identifications a strong possibility.
Region iv (1.5 < E50 < 4.0 keV and 0.1 < Fx /FKs < 10) in
Figure 8 contains 12 medium and high count rate unidentified ChIcAGO sources. However, there are no identified
ChIcAGO or archival sources in this region that could indicate any likely source populations. The best clue comes from
Figure 7, which shows that these unidentified sources are in
the same region of this plot as the identified ChIcAGO and
archival AGN. In the Galactic plane, the log N − log S relation
of X-ray sources in the 2.0 − 10.0 keV energy range (see Figure 15 of Hands et al. 2004), demonstrates that within the
X-ray flux range 1 × 10−13 < Fx < 2 × 10−12 of Region iv,
between 0.06 and 8 extragalactic sources are expected per
square degree. These number densities are consistent with
more recent log N − log S modeling conducted by Mateos et al.
(2008) who used 1129 XMM observations at |b| > 20◦ to
demonstrate that sources in the 2 − 10 keV energy range, at
high Galactic latitudes, agree with AGN models to better than
10%. As the ChIcAGO sources in Region iv have a number density < 8 deg−2 it is not unreasonable to speculate that
the many of the unidentified ChIcAGO sources in this region
could be AGN. However, we compared the NH values of the
Region iv ChIcAGO sources calculated from the power law
quantile analysis and spectral fits in Table 3 to the Galactic
column densities in their direction from surveys conducted by
Kalberla et al. (2005) and Dickey & Lockman (1990).37 In all
37
online
The
Galactic column densities were obtained using the
HEASARC
calculator
http://heasarc.gsfc.nasa.gov/cgi-
17
by four cases the ChIcAGO sources have NH values an order
of a magnitude lower than the Galactic NH , suggesting a possible Galactic origin. The ChIcAGO sources ChI J181116–
1828_2, ChI J181213–1842_7, ChI J190749+0803_1, and
ChI J194152+2251_2 have NH values of the same order as the
Galactic column density (NH = 1.2 × 1022 , 1.3 × 1022 , 1.5 ×
1022 , and 1.1 × 1022 cm−2 , respectively, Kalberla et al. 2005),
which is more indicative of an extragalacitc origin and therefore an AGN identification. Further investigation is required
to confirm the nature of the Region iv population.
Region v (1.5 < E50 < 4.0 keV and 10 < Fx /FKs < 50) of Figure 8 encompasses the two identified archival CVs and the
lower Fx /FKs ratio limit of unidentified ChIcAGO source ChI
J181852-1559_2. As its flux ratio is only a lower limit (corresponding to an upper-limit on the K-band flux), it is possible
that ChI J181852-1559_2 may instead be a member of Region
vi (described below).
Region vi (1.3 < E50 < 4.0 keV and Fx /FKs > 1 × 102 ) contains four identified archival magnetars. The only unidentified
ChIcAGO source that sits within this region is ChI J1538185541_1. Based on its proximity to these magnetars, it is possible that ChI J153818-5541_1 could also be a magnetar, however, its X-ray emission is much harder in comparison. Regardless, the position of ChI J153818-5541_1 in Figure 8 indicates that this source is definitely worthy of further study.
4.2.2. Infrared Population Statistics
In order to further refine the possible populations within Figure 8, we investigated the infrared colors of the unidentified ChIcAGO sources, once again drawing comparisons with
the identified ChIcAGO and archival sources. As mentioned
above, there is strong evidence in Figure 8 that some of the
unidentified ChIcAGO sources in Region ii could be massive
stars such as WR and Of stars, and perhaps even CWBs. It
is also possible that many of the ChIcAGO sources, particularly in Region i, are PMS stars given their similar X-ray-toinfrared flux ratio to the COUP stars in Figure 8. However,
for the purposes of this paper we have chosen to concentrate
on the selection criteria for the hard X-ray emitting massive
stars. We therefore leave the investigation of the PMS star
population in the ChIcAGO survey for future work (for infrared selection criteria for PMS stars see Favata et al. 2005;
Maercker & Burton 2005; Maercker et al. 2006).
Hadfield et al. (2007) created a selection criterion for WR
stars using GLIMPSE and 2MASS magnitudes, which was
further refined by Mauerhan et al. (2011). Figures 9(a) and
9(b) are recreations of the Hadfield et al. (2007) [3.6]-[4.5] vs
[3.6]-[8.0] and J − Ks vs Ks − [8.0] color-color plots, showing the unidentified ChIcAGO sources. (The numbers in
brackets correspond to the effective wavelength in µm of
the GLIMPSE magnitude bands.) The dashed lines in Figures 9(a) and 9(b) indicate the color space used by Mauerhan
et al. (2011) to select WR candidates. These color spaces indicate where WR stars are expected to fall, in comparison to
field stars, due to the infrared excess of WR stars resulting
from free-free emission generated in their strong, dense stellar winds (see Mauerhan et al. 2011, and references therein).
In Figures 9(a) and 9(b), the unidentified ChIcAGO sources
(UChI) have been separated into different colored symbols
bin/Tools/w3nh/w3nh.pl
18
Figure 9. Infrared and near-infrared color-color diagrams illustrating the selection criteria of Hadfield et al. (2007) and Mauerhan et al. (2011) for WR stars. (a)
3.6 µm − 4.5 µm vs 3.6 µm − 8.0 µm. (b) J − Ks vs Ks − 8.0 µm. In both plots the dashed lines indicated the WR color space used by Mauerhan et al. (2011).
The unidentified ChIcAGO sources (“UChI”) are represented by red, blue and black for Regions i, ii, and iii, respectively. The identified ChIcAGO and archival
AGPS sources that are WRs and LBVs (green), massive O-type stars (pink), all other non-degenerate stars (yellow) and HMXBs (grey) are also represented. The
dots represent those sources that have accurate photometric information in the magnitude bands plotted. The crosses indicate those source for which we have
used their GLIMPSE 5.8 µm magnitude in the absence of a GLIMPSE 8.0 µm detection. The Region iv sources in Figure 9(b) (cyan crosses) were not detected
at 5.8 or 8.0 µm, so their 4.5 µm magnitudes were used instead. The triangles mark sources for which the J magnitude is a lower-limit. The diamonds mark
sources for which the Ks magnitude is a lower-limit.
T HE C H I C AGO S URVEY
based on whether they are in Region i (red), Region ii (blue),
or Region iii (black). In both these Figures, the majority of
unidentified ChIcAGO sources, particularly from Region i, do
not have an infrared excess so cluster together near the origin
where Hadfield et al. (2007) state the general stellar locus is
located. These unidentified ChIcAGO sources are therefore
unlikely to have strong stellar winds, so are more likely to
have active stellar coronae. There are, however, several Region ii sources, and three Region i sources, that have more
unusual colors, falling within, very close or below the indicated WR color spaces. (It should be noted that many of these
unusually colored unidentified ChIcAGO sources only have
magnitude lower limits in one or more of the filter bands,
making their positions in these color-color diagrams uncertain. See Figures 9(a) and 9(b) for details on these magnitude
limited sources.)
Rather than keeping the original identified source categories we have instead separated the identified ChIcAGO and
archival massive stars and CWBs into categories based on
their dominant stellar components. These categories are WR
and LBVs (green data points), massive O type stars (pink
data points), and all other non-degenerate stars (yellow data
points). The HMXBs are still indicated by grey data points.
The identified WR stars fall within one or both of the Mauerhan et al. (2011) WR color spaces in Figures 9(a) and
9(b). Based on their positions within one or both WR color
spaces, it is possible that the unidentified Region ii ChIcAGO
sources ChI J181915–1601_2, ChI J180857–2004_2 and ChI
J183345–0828_1 may also be WR stars. In fact, using
this color space technique Hadfield et al. (2007) identified
the 2MASS counterpart of ChI J181915–1601_2, 2MASS
J18192219âĹŠ-1603123, as a WR star and further classified
it as a WN7o star using spectroscopy. There are also three Region i unidentified ChIcAGO sources, ChI J154557–5443_1,
ChI J154557–5443_3, and ChI J172550–3533_2, whose magnitude limits fall within the WR color space of Figure 9(b) and
below the WR color space of Figure 9(a), which may also be
worth further investigation.
The identified ChIcAGO source AX J144547-5931 (an Of
type star, which is also shown as a pink dot in Figures 7
and 8, see Anderson et al. 2011) sits to the left of both WR
color spaces in Figures 9(a) and 9(b). The unidentified Region
ii ChIcAGO sources ChI J182435–1311_1, ChI J182651–
1206_4, ChI J183356–0822_3, and ChI J184652–0240_1 are
also located in this same vicinity as AX J144547–5931 in one
or both Figures (within 0.2 < [3.6] − [8.0] < 0.5 in Figure 9(a)
and within 0.5 < Ks − [8.0] < 1.2 in Figure 9(b)). While these
four unidentified ChIcAGO sources have unusual infrared
colors, they are not as extreme as those of typical WR stars.
Given their proximity in Figure 9 to the Of star AX J1445475931, it is possible that these unidentified ChIcAGO sources
could be similar massive O-type stars. The remaining Region
ii ChIcAGO sources lie within the general stellar locus of Figures 9(a) and 9(b), so could be massive stars, active stellar
coronae, or PMS stars.
The archival HMXBs also have unusual infrared colors as
they fall within or above the top edge of the WR color spaces
in Figures 9(a) and 9(b). These infrared colors may be due to
intrinsic absorption (for example see Rodriguez et al. 2006).
Several unidentified Region ii ChIcAGO sources also lie close
to the HMXBs in these Figures, but as they have much softer
19
median X-ray energies (see Figure 8), such an identification
is unlikely. ChI J170017–4220_1 is the only Region iii source
with sufficient infrared magnitude information to be displayed
in Figures 9(a) and 9(b). This unidentified ChIcAGO source
falls within the vicinity of the HMXBs in Figure 8 but has
much more extreme infrared colors, and lies above the WR
color space in both color-color plots. Further investigation is
required to confirm the X-ray binary nature of ChI J170017–
4220_1.
None of the 11 unidentified Region iv ChIcAGO sources have
been detected at 8 µm, with only three, ChI J163751–4656_1,
ChI J165420–4337_1, and ChI J190818+0745_1, detected
with GLIMPSE at 3.6 and 4.5 µm, all of which are likely
to be Galactic in origin (see Section 4.2.1). In Figure 9(b) we
have plotted these three unidentified ChIcAGO sources using
their 4.5 µm magnitude in place of 8 µm magnitude. Only
ChI J165420-4337_1 falls within the WR color space. Given
the extreme uncertainties associated with the Ks − [8.0] color
of ChI J165420-4337_1, no conclusions can be drawn about
its possible nature.
4.3. Further Discussion of Interesting ChIcAGO and AGPS
Sources
We have flagged several of the unidentified ChIcAGO sources
as interesting and worthy of future follow-up based on their
X-ray and infrared properties explored in Section 4.2. These
population statistics have also allowed us to make some tentative identifications. The details of these sources are described
below. There are several unidentified ChIcAGO sources that
are not detailed in this Section but are listed, along with their
tentative identification based on the population statistics, in
Table 12.
4.3.1. ChI J144519–5949_2
ChI J144519–5949_2 is one of the six ChIcAGO sources detected within the H II region GAL 316.8–00.1 (see Table 9).
As it does not have a GLIMPSE counterpart, it is not included in Figures 9(a) and 9(b). However, its 2MASS counterpart, 2MASS 14452143-5949251, has unusual colors and
falls within the WR color space of the J − H vs H − Ks plot
in Figure 1 of Mauerhan et al. (2011). We therefore tentatively identify ChI J144519–5949_2 as a candidate WR star.
Given the location of ChI J144519–5949_2 in Region ii of
Figure 8, particularly near two identified CWBs, it is very
likely that this star has very strong winds that are generating
X-rays through instability-driven wind-shocks. This object
could even possibly be a CWB (for example see Anderson
et al. 2011).
4.3.2. ChI J150436-5824_1
Several unidentified AGPS sources have been investigated by
Degenaar et al. (2012) using the X-ray telescope (XRT) on
the Swift satellite (Gehrels et al. 2004). Degenaar et al. (2012)
suggest that ChI J150436-5824_1 (which they publish under
the AGPS name AX J1504.6–5824) could possibly be associated with a main sequence star that falls within the 90% XRT
error circle. However, the ChIcAGO Chandra observation of
ChI J150436-5824_1 demonstrates that there is no cataloged
counterpart within the < 100 position error circle of this X-ray
source, arguing against this tentative identification.
20
4.3.3. ChI J153818–5541_1
In Figure 7, ChI J153818–5541_1 has properties that are
clearly not consistent with the stellar or AGN populations.
It sits near the bottom right-hand corner of Figure 7, having
similar X-ray and infrared fluxes to the archival magnetars
(black data points). ChI J153818–5541_1 also falls within
Region vi in Figure 8 along with these same magnetars, further indicating a possible magnetar nature. However, during
the writing of this paper, recent studies with Swift have indicated that ChI J153818–5541_1 (published under its AGPS
name AX J1538.3–5541) may in fact be a low mass X-ray binary (LMXB; Degenaar et al. 2012). If this is the case, then
X-ray and infrared statistical analysis is not a foolproof diagnostic. That being said, this same statistical analysis has
allowed us to show that interesting and unusual Galactic Xray sources fall within Region vi of Figure 8. (It should be
noted that a magnetar identification for this source has not
been completely ruled out.)
4.3.4. ChI J154557–5443_3
ChI J154557–5443_3 is a soft X-ray source as demonstrated
by its isolated position in Figure 7. Only 2 X-ray counts,
from a total of 22 detected with Chandra, had an energy
> 2 keV, but otherwise the source’s median energy (E50 =
0.8 keV) is consistent with the other sources in Region i
of Figure 8. The X-ray-to-optical flux ratio for this source
is log[F(x,0.3−8keV) /FR ] = −2.5 (where FR = λFR,λ using the R
magnitude band), which is consistent with what is expected
from stars and normal galaxies (Mainieri et al. 2002). An
unusual property of this source is its position in WR color
space in Figure 9(b), but this may result from using its 5.8 µm
GLIMPSE magnitude in place of a lacking 8.0 µm magnitude. An optical or infrared spectrum would likely reveal the
identity of this source. ChI J154557–5443_3 is therefore unlikely to be related to AX J154557–5443 as ASCA only detected hard counts (> 2 keV) from this AGPS source.
4.3.5. ChI J162011–5002_1
Degenaar et al. (2012) tentatively identified ChI J162011–
5002_1 (published under its AGPS name AX J1620.1–5002)
as a candidate accreting magnetized white dwarf based on its
hard X-ray spectrum described by a flat power law, and lack
of any cataloged optical/infrared counterpart. The power-law
index obtained using quantile spectral interpolation (see Table 3) agrees with the result from Degenaar et al. (2012) and
is consistent with the spectra of magnetically accreting white
dwarfs (Γ < 1; Muno et al. 2003). However, our analysis resulted in a higher column density than the value calculated by
Degenaar et al. (2012, NH . 3 × 1021 cm−2 ). Deep imaging
in the H-band with PANIC resulted in the detection of a faint
counterpart (H = 17.01 ± 0.14). Further follow-up is required
to confirm this classification.
4.3.6. AX J162246–4946
The newly discovered radio and X-ray emitting magnetar,
PSR J1622–4950 (also known as CXOU J162244.8–495054,
Evans et al. 2010; Levin et al. 2010), was not cataloged by
ChIcAGO MAP. This is because it lies 40 from the position
of AX J162246–4946, and is therefore outside the 30 radius
for which ChIcAGO MAP searches for X-ray point sources.
However, PSR J1622–4950 was detected in this ChIcAGO
Chandra observation and further investigation in Anderson
et al. (2012) demonstrates that this magnetar may have contributed up to 75% of the X-ray emission originally detected
by ASCA from AX J162246–4946. We therefore identify AX
J162246–4946 as PSR J1622–4950, and this source has been
included as an identified magnetar in Figures 7 and 8. (For
further discussion on X-ray point sources detected beyond the
30 search radius surrounding the AGPS position see Appendix
B.)
4.3.7. AX J165951–4209
While Sugizaki et al. (2001) reported an absorbed flux of
Fx = 4.04 × 10−12 erg cm−2 s−1 from AX J165951–4209 in the
0.7 − 10.0 keV band, this AGPS source was not detected in
the ChIcAGO Chandra observation on 2008 June 21, with an
upper limit on any X-ray flux of Fx ∼ 5 × 10−14 erg cm−2 s−1
(0.3 − 8 keV). AX J165951–4209 was also not detected with
the Swift XRT on 2008 January 23 (Degenaar et al. 2012) at a
flux level of Fx ∼ 3 × 10−13 erg cm−2 s−1 (0.3 − 10 keV). While
variability of several orders of magnitude (in this case a factor of ∼ 100) is typical behavior of both Be X-ray binaries
(BeXs; Reig 2011) and black hole transients (McClintock &
Remillard 2006), the hard power law index calculated from
the ASCA spectrum of this source (Γ ∼ 0.47; Sugizaki et al.
2001) is quite hard. This power law index is harder than what
is usually observed from black hole transients (McClintock &
Remillard 2006) but is consistent with spectra from BeXs (for
example see Haberl et al. 2008). We therefore suggest that
AX J165951–4209 could be a transient BeX.
4.3.8. ChI J170017–4220_1
ChI J170017–4220_1 (also known as AX J1700.2–4220)
has long been assumed to be a HMXB (see Liu et al.
2006; Bird et al. 2007; Krivonos et al. 2007; Bird et al.
2010). This is, however, unconfirmed and is partly based
upon the assumption that the Be star HD 153295 (2MASS
J17002524-4219003) is the counterpart to ChI J170017–
4220_1 (Negueruela & Schurch 2007). The ChIcAGO Chandra observation shows that HD 153295 is actually the counterpart to ChI J170017–4220_2 (see Table 7) and that ChI
J170017–4220_1 has no 2MASS counterpart. The main clue
to the nature of ChI J170017–4220_1 comes from Markwardt
et al. (2010), who detected a 54s X-ray pulse period and 44
day orbital period using archival XMM and Rossi X-ray Timing Explorer data. These period values are suggestive of a Be
HMXB (Markwardt et al. 2010).
We obtained PANIC NIR observations of ChI J170017–
4220_1 and identified its GLIMPSE counterpart, allowing this
ChIcAGO source to be represented in Figures 7, 8, and 9. ChI
J170017–4220_1 is part of Group 2 in Figure 7, and is therefore consistent with an AGN, but this source is also situated in
the same region as the archival HMXBs in Figure 8. Its placement on Figures 9(a) and 9(b) demonstrates that it has very
unusual infrared colors, even more extreme than the archival
HMXBs, which could indicate strong winds or a large amount
of circumstellar absorption. Further investigation is required
to determine the true nature of ChI J170017–4220_1.
4.3.9. ChI J172050–3710_1
T HE C H I C AGO S URVEY
Degenaar et al. (2012) suggested that ChI J172050–3710_1
(also known as AX J1720.8–3710) may be associated with
the NIR source 2MASS J17205180-3710371, which has colors similar to a main sequence star. They also suggested that
the low absorption inferred from a power-law X-ray fit indicates that ChI J172050–3710_1 may be a foreground star.
We agree that this 2MASS source is the likely counterpart to
ChI J172050–3710_1 based on the position obtained with the
ChIcAGO Chandra observation (see Table 2). We also agree
that the counterpart colors are unremarkable (see Figures 9(a)
and 9(b)), given that they are consistent with the general stellar locus depicted in Figure 1 of Hadfield et al. (2007). Our
quantile thermal bremsstrahlung spectral interpolation of ChI
J172050–3710_1 (see Table 4) also predicts a low value of
NH . This, combined with the unremarkable colors of 2MASS
J17205180-3710371, and the fact that this ChIcAGO source is
situated in Region i of Figure 8 with the other soft X-ray emitting stars, supports the claim by Degenaar et al. (2012) that
ChI J172050–3710_1 is likely a foreground main sequence
star. We therefore argue that the likely source of X-ray emission from ChI J172050–3710_1 is generated in an active stellar corona.
4.3.10. ChI J180857–2004_2
ChI J180857–2004_2 falls within the inner edge of the infrared dust bubble CN 148 (Churchwell et al. 2007). Such
bubbles are formed by the stellar winds of young hot stars impacting the interstellar medium (Churchwell et al. 2006). The
morphology of the dust cloud immediately surrounding ChI
J180857–2004_2 demonstrates a shell-type structure. This
could indicate that its stellar winds are impacting the environment and generating a small secondary bubble within CN
148. If this is the case, then ChI J180857–2004_2 could be
a young massive star with strong stellar winds. This is already indicated by its position within the WR color spaces
in Figures 9(a) and 9(b), and by the detection of hard X-ray
emission with Chandra, indicated by its position within Region ii of Figure 8. ChI J180857–2004_2 could therefore be
a WR star, for which the X-ray emission is generated through
instability-driven wind-shocks or in a CWB (see Anderson
et al. 2011).
4.3.11. ChI J181116–1828_5
ChI J181116–1828_5 is a faint point source detected in the
Chandra observation of AX J181116–1828 so it is unlikely
to be the main contributor of X-ray emission to this AGPS
source. This source is, however, quite hard, with all but one
count having an energy > 2 keV, and is coincident with a
MAGPIS radio source with a core-lobe morphology (see Section 3.4). Given the morphology of its likely radio counterpart, along with the detection of predominately hard X-rays
(E50 = 3.4 keV), we tentatively identify ChI J181116-1828_5
as an AGN.
4.3.12. ChI J181852–1559_2
During the writing of this paper, ChI J181852–1559_2 (also
known as AX J1818.8–1559) was proposed as a magnetar
candidate through the analysis of several X-ray observations
(Mereghetti et al. 2012). This proposed identification is encouraging as the lower limit of ChI J181852–1559_2 in Figure 8 is consistent with the archival magnetars in Region vi,
21
demonstrating the usefulness of this statistical plot for identifying interesting sources.
4.3.13. ChI J181915–1601_2
As mentioned in Section 4.2.2, Hadfield et al. (2007) identified 2MASS J18192219–1603123 (the counterpart to ChI
J181915–1601_2, see Table 2) as a WR star of type WN7o
using the same selection criteria that we have adopted in Figures 9(a) and 9(b). The mechanism behind the production
of X-ray emission is still unknown, but is likely caused by
massive stellar winds as demonstrated by the position of ChI
J181915–1601_2 within Region ii of Figure 8. Further investigation is required to determine if this WR star is mainly
producing X-ray emission through instability-driven windshocks, or if it is part of a CWB.
4.3.14. ChI J183345–0828_1
Kargaltsev et al. (2012) identified 2MASS J18334038–
0828304 as the counterpart to ChI J183345–0828_1 (also
known as CXOU J183340.3–082830), but the nature of this
X-ray source is still unknown. ChI J183345–0828_1 falls
within an extended X-ray source in SNR G23.5+0.1, which
Kargaltsev et al. (2012) have tentatively identified as the PWN
powered by PSR B1830–08. It is possible that both this PWN
and ChI J183345–0828_1 may have contributed to the X-ray
emission originally detected by ASCA from AX J183345–
0828. While ChI J183345–0828_1 is unlikely to be associated
with the PWN, given the relative brightness of its IR counterpart, it does fall within the WR color space in Figure 9(b).
ChI J183345–0828_1 could therefore be a massive star with
strong stellar winds.
4.3.15. ChI J184741–0219_3
As mentioned in Section 3.4, ChI J184741–0219_3 is coincident with a MAGPIS radio source that has a core-lobe morphology. Deep PANIC observations also allowed the detection of its infrared counterpart (K = 18.46), which places it
in Region iii of Figure 8 (represented by the smallest cyan
data point) along with the other archival AGN AX J183039–
1002 (Bassani et al. 2009), which is the middle sized cyan
data point. (We obtained the NIR magnitudes J > 20.6 ± 0.3,
H = 17.3 ± 0.2 and Ks = 14.3 ± 0.2 on 2007 July 29 for AX
J183039–1002 using PANIC.) As ChI J184741–0219_3 had
by far the highest count-rate of all sources detected in the 30
Chandra region around the aim-point for this target (see Table 1), it is likely the main contributor to the X-ray emission
detected from AX J184741–0219 in the AGPS.
ChI J184741–0219_3 has a hard X-ray spectrum (see Table 3)
where the resulting absorbed X-ray flux from the power-law
spectral interpolation is Fx = 2.6 ± 0.5 × 10−13 erg cm−2 s−1 in
the 0.3 − 8 keV energy band. Using the same spectral interpolation parameters and the ASCA count-rates (Sugizaki et al.
2001), Chandra PIMMS estimates that ChI J184741–0219_3
had an absorbed X-ray flux of Fx ≈ 1 × 10−12 erg cm−2 s−1
during the 1999 AGPS observation. Degenaar et al. (2012)
also observed the field of ChI J184741–0219_3 with the Swift
XRT in 2007 March but only obtained an absorbed X-ray flux
upper-limit of Fx < 1 × 10−13 erg cm−2 s−1 (0.3 − 10 keV).
These flux measurements suggest likely long-term variability from this source. We therefore tentatively identify ChI
J184741–0219_3 as an X-ray variable AGN.
22
4.3.16. AX J185905+0333
4.4.3. ChI J172550–3533_2
Suzaku observations have demonstrated that AX
J185905+0333 is likely an X-ray luminous cluster of
galaxies behind the Galactic Plane (Yamauchi et al. 2011).
The extended nature of this source is the likely reason it was
not detected in the short ChIcAGO Chandra observation.
Using the position obtained with the ChIcAGO Chandra observation, we identified ChI J172550–3533_2 as the dwarf
Nova V478 Sco (Vogt & Bateson 1982). ChI J172550–
3533_2 has a soft X-ray spectrum, as indicated by its position within Region i of Figure 8, but has quite unusual infrared colors based on its position below the WR color-spaces
in Figures 9(a) and 9(b).
4.3.17. AX J191046+0917
AX J191046+0917 (also known as AX J1910.7+0917), while
not detected in the ChIcAGO Chandra observation, has been
detected intermittently in a small number of ASCA, XMM, and
Integral observations, allowing Pavan et al. (2011) to identify
it as a likely HMXB candidate. Further X-ray observations are
required to confirm such an identification and further refine its
class.
4.3.18. ChI J194939+2631_1
During the writing of this paper, ChI J194939+2631_1 (also
known as AX J194939+2631) was identified as a CV by Zolotukhin & Chilingarian (2011) using the ChIcAGO Chandra
observation and the Isaac Newton Telescope Photometric Hα
Survey of the northern Galactic plane (IPHAS; Drew et al.
2005). Further follow-up is required to confirm their tentative
intermediate polar (IP) classification.
4.4. ChIcAGO Sources Identified with SIMBAD
We were also able to identify four of the bright (> 20 X-ray
counts) ChIcAGO sources using the SIMBAD Astronomical
Database. These four ChIcAGO sources are described below. We also discuss the secondary ChIcAGO source ChI
J165420–4337_2.
4.4.1. ChI J144042–6001_1
The position obtained with the ChIcAGO Chandra observation confirms the Sugizaki et al. (2001) identification of ChI
J144042-6001_1 (also known as AX J144042–6001) as the
PMS star HD 128696. This source appears as an identified
star (yellow data point) in group 1 of Figure 7, in Region i
of Figure 8, and is consistent with the general stellar locus in
Figures 9(a) and 9(b).
4.4.2. ChI J165420–4337_2
Sugizaki et al. (2001) identified AX J165420–4337 as the K5
type star HD 326426. After observing the ASCA position
of AX J165420–4337 with Chandra HRC, we detected two
ChIcAGO sources ChI J165420–4337_1 (123 X-ray counts
detected) and ChI J165420–4337_2 (16 X-ray counts detected). As ChI J165420–4337_1 is by far the brightest of
the ChIcAGO sources detected in this Chandra observation,
it is therefore likely to be the main source of X-ray emission originally detected in the AGPS. The fainter (secondary)
ChIcAGO source in the field, ChI J165420–4337_2, is in fact
the X-ray counterpart to HD 326426 based on position comparisons using SIMBAD. Therefore the identification of AX
J165420–4337 as HD 326426 by Sugizaki et al. (2001) is incorrect.
4.4.4. ChI J172642–3540_1
Using SIMBAD, we identified ChI J172642–3540_1 as the
X-ray counterpart to the K2V type star CD-35 11565 (Torres
et al. 2006). ChI J172642–3540_1 is soft, like the other stars
in Region i of Figure 8. Its position in Figures 9(a) and 9(b)
is also consistent with the general stellar population.
4.4.5. ChI J194310+2318_5
ChI J194310+2318_5 is one of the 18 ChIcAGO sources detected within the H II region G59.5–0.2 (see Section 4.1 and
Table 9). Using SIMBAD and the Chandra position for this
source, we determined that ChI J194310+2318_5 is the X-ray
counterpart to the O7V((f)) type star HD 344784 (Walborn
1973). This source is quite soft (within Region i of Figure 8)
and has unremarkable infrared colors (see Figures 9(a) and
9(b)). The placement of ChI J194310+2318_5 in the aforementioned Figures, combined with its stellar classification,
make this ChIcAGO source compatible with an active stellar
corona identification.
4.5. Confirmed and Tentative Identifications of the AGPS
Sources
Table 12 reproduces the original list of the 163 AGPS sources
from Sugizaki et al. (2001), but now including the corresponding ChIcAGO sources with > 20 X-ray counts in column two.
The confirmed or tentative identification of these ChIcAGO
sources are listed in the third column, where the abbreviations
are given in the Table caption. Those AGPS sources and corresponding ChIcAGO sources with confirmed identifications
were either obtained from the literature, and are therefore
called “archival AGPS” sources, or were obtained through
the ChIcAGO survey’s Chandra observations (i.e. this paper and Anderson et al. 2011, 2012). The tentative identifications were made through the multi-wavelength follow-up and
population statistics conducted on the ChIcAGO sources in
Section 4.2. The forth column gives the most common name
for the AGPS and/or ChIcAGO source while column five lists
the references from which the X-ray and infrared properties
of a given source was obtained for use in the statistical plots
(Figures 7, 8 and 9).
The tentative identifications of the ChIcAGO sources are
based on the statistical plots in Section 4.2. For example, if
a ChIcAGO source falls within Region i of Figure 8, then
its type in Table 12 has been listed as being either an active stellar corona (ASC) or PMS star (ASC/PMS). If the
ChIcAGO source falls within Region ii of Figure 8, and also
within one or both of the WR color spaces in Figures 9(a) and
9(b), then its type has been classified as a WR star. Those
ChIcAGO sources that fall within Region ii of Figure 8 and
near AX J144547-5931 in Figures 9(a) and 9(b) (see text in
T HE C H I C AGO S URVEY
Section 4.2.2) have been classified as massive O-type stars
(MS-O). All Region ii stars that fall within the general stellar loci of Figures 9(a) and 9(b) could be either massive stars
(MS) or ASC so are listed as MS/ASC. (A PMS star interpretation is also possible for these Region ii sources.)
Those Region ii ChIcAGO sources listed as Wolf-Rayet
(WR), massive stars (MS), or massive O-type stars (MS-O),
still need to be properly investigated for evidence of X-ray
emission emanating from colliding-winds in a CWB. Such an
identification requires further X-ray spectroscopic follow-up
to identify plasma temperatures between 1 and 10 keV (Usov
1992). There are also 7 AGPS sources that are listed as H
II regions. Those AGPS sources identified as “H II ” are actually made up of many X-ray point sources that were detected in our ChIcAGO Chandra observations (see Section
4.1) and are therefore young and massive stars in the H II
region listed. If there is an identified X-ray star that is a significant contributor to the X-ray emission, the stellar type is
listed before the H II abbreviation in column 3, along with
its ChIcAGO source name in column 2. The suffixes of the
other ChIcAGO sources coincident with the H II region are
listed in parentheses. All other AGPS and ChIcAGO sources
for which there is no identification information are classified
as unknown (U). If no sources were detected in a ChIcAGO
Chandra observation, then the AGPS source falls in the no detection (ND) category. A detailed description of some of the
AGPS sources identified through the ChIcAGO survey and of
the archival AGPS sources (i.e. those sources identified in the
literature and therefore not observed with Chandra as part of
the ChIcAGO survey) can be found in Section 4.3 and Appendix A, respectively.
The final column in Table 12 contains a flag for columns one
and two that indicates whether an AGPS and/or ChIcAGO
source has a confirmed identification (I) obtained through
work in the ChIcAGO survey or a tentative identification (T)
using the population statistics in Section 4.2. Those AGPS
sources for which no ChIcAGO sources were detected within
30 of the ASCA position, or only faint (< 20 X-ray counts)
ChIcAGO sources were detected (F), are also indicated. (This
flag excludes those AGPS sources that have been identified
as H II regions.) The unidentified population of ChIcAGO
sources that fall in Region iv of Figure 8 (R) are also included.
There is also a flag for column three that indicates whether the
type identification for a ChIcAGO source is unconfirmed (N)
due to it being based on its tentative statistical identification
in Section 4.2.
5. CONCLUSIONS
The main aim of the ChIcAGO survey is to identify the
Galactic plane X-ray source populations that make up the
Fx ∼ 10−13 to 10−11 erg cm−2 s−1 flux range. To achieve this
we have used new observations from the Chandra X-ray telescope, along with extensive multi-wavelength follow-up, to
identify sources from the ASCA Galactic Plane Survey (Sugizaki et al. 2001). We have reported observations of the
ASCA positions of 93 unidentified AGPS sources with Chandra, from which a total of 253 X-ray point sources, termed
“ChIcAGO sources”, have been detected.
Through visual inspection of Galactic plane radio surveys,
we have found 5 ChIcAGO sources within supernova remnants that have no cataloged optical or infrared counter-
23
parts. These sources could potentially be compact objects
associated with their surrounding SNRs. Further radio analysis has also demonstrated that the ChIcAGO sources detected in the Chandra observations of the AGPS sources AX
J144519–5949, AX J151005–5824, AX J154905–5420, AX
J162208–5005, AX J194310+2318, AX J194332+2323, and
AX J195006+2628 are all coincident with H II regions. Table 11 demonstrates that the range of luminosities, which are
calculated using kinematic distances to the H II regions, are
consistent with the luminosities we expect from flaring PMS
stars, massive stars, and CWBs. We therefore identify the 54
separate ChIcAGO sources seen in these Chandra observations as young and massive stars within H II regions.
Of the 93 Chandra-observed AGPS fields, 62 have one or
more sources with > 20 X-ray counts, resulting in the detailed study of 74 ChIcAGO sources in this paper. The multiwavelength follow-up of these ChIcAGO sources demonstrates the need for Chandra’s subarcsecond localization capabilities to correctly identify likely infrared and optical counterparts. The main focus of this paper has been on those
unidentified ChIcAGO sources with > 20 X-ray counts and
with near-infrared or infrared counterparts. This has allowed us to perform population statistics to identify some
of the likely objects that make up the Fx ∼ 10−13 to 10−11
erg cm−2 s−1 Galactic plane X-ray source populations.
We have developed a new statistical diagnostic for identifying likely populations of X-ray emitting sources using Kband fluxes and upper-limits (see Figure 8). The unidentified
ChIcAGO sources in Region i of Figure 8 have soft X-ray
emission and low X-ray-to-infrared flux ratios, making them
consistent with many of the archival and identified ChIcAGO
stars. Their X-ray-to-infrared flux ratios are also similar to
the COUP stars (see Figure 7), which are predominantly PMS
stars. The majority of the Region i sources also fall within the
general stellar locus that is expected in Figures 9(a) and 9(b)
(Hadfield et al. 2007). They are therefore likely to be active
stellar coronae, which is consistent with the main soft X-ray
populations expected in the Galactic plane (Hong et al. 2005),
or PMS stars.
Many of the ChIcAGO sources in Region ii of Figure 8 have
infrared colors similar to known Wolf-Rayet stars, as demonstrated in Figure 9, which indicate the presence of excess
infrared emission resulting from strong, dense stellar winds.
These sources are therefore likely to be massive stars generating X-rays through instability-driven wind shocks or even
colliding winds in CWBs (for example see Anderson et al.
2011).
Only two unidentified ChIcAGO sources are located within
Region iii of Figure 8, along with the archival high-mass and
symbiotic X-ray binaries (and AGN). As such X-ray binaries
(XRBs) are rare, only a few unidentified ChIcAGO sources
are expected to fall within this group. This result therefore
demonstrates that Figure 8 may be a very useful diagnostic
for identifying XRBs.
Region vi contains four identified magnetars and a candidate
LMXB. Even though there are likely two different source populations in Region vi, Figure 8 demonstrates that hard X-ray
sources (E50 > 1.3 keV), with an X-ray-to-infrared flux ratio Fx /FKs > 102 , are very rare and interesting Galactic X-ray
sources.
24
The population of ChIcAGO sources in Region iv of Figure 8 remains unidentified. Based on their position relative
to the identified AGN in Figure 7 and they high NH values
compared to the Galactic column density, we suggest that
the 4 ChIcAGO sources ChI J181116–1828_2, ChI J181213–
1842_7, ChI J190749+0803_1, and ChI J194152+2251_2
could be background AGN. The remaining 8 unidentified Region iv ChIcAGO sources have far lower NH values than the
Galactic column densities indicating that they could be located in our own Galaxy. Optical and infrared spectroscopic
follow-up is required to identify the true nature of this population.
With further source identifications, a full log N − log S model
of the hard (2 − 10 keV) Galactic plane X-ray populations between Fx ∼ 10−13 and 10−11 erg cm−2 s−1 will be able to be
constructed. This log N − log S will be more complete than
those constructed from previous X-ray surveys in the same
flux range, as it will be representative of 40 deg2 of the Galactic plane. It will also show individual contributions from
different Galactic X-ray source populations including nonaccretion powered sources such as CWBs, SNRs, PWNe, and
magnetars, which have not been a focus of previous work. Using the log N − log S distribution and distance estimates, it will
then be possible to construct luminosity functions and threedimensional spatial distributions of each class of X-ray source
in the Galactic plane.
APPENDIX
SOURCE DESCRIPTIONS OF THE ARCHIVAL AGPS SOURCES
As mentioned in Section 1, approximately one third of the AGPS sources were identified by Sugizaki et al. (2001) or were
classified by other research groups prior to the ChIcAGO survey. It is these identified AGPS sources, referred to as “archival
sources” in Section 4.2.1, which have been used to narrow down the possible unidentified ChIcAGO source populations. The
archival AGPS sources are listed in Table 12 and are briefly described in below.
AX J143416–6024 RS CVn type variable star, HD 127535, with spectral type K1IIIe (Sugizaki et al. 2001).
AX J155052–5418 X-ray and radio emitting magnetar 1E 1547.0-5408, associated with the possible radio SNR G327.24-0.13
(Gelfand & Gaensler 2007).
AX J155644-5325 KOIIIe type star, TYC 8697–1438-1 (Torres et al. 2006).
AX J161929–4945 SFXT, a sub-class of HMXBs that display fast X-ray outbursts (Sguera et al. 2006; Tomsick et al. 2006).
AX J162155–4939 K3III type star, HD 147070 (Sugizaki et al. 2001); this identification needs to be confirmed by follow-up
X-ray observations
AX J163159–4752 Accretion driven 1300s X-ray pulsar in a supergiant HMXB (Rodriguez et al. 2006; Walter et al. 2006). This
system is one of the highly absorbed HMXBs identified by Integral (Negueruela & Schurch 2007).
AX J163351–4807 The magnetic Of?p star HD 148937 (Nazé et al. 2012).
AX J163555–4719 The X-ray emission associated with SNR G337.2+0.1 and its PWN (Combi et al. 2006). This system is also
associated with the Fermi-LAT source 1FGL J1635.7–4715 (Abdo et al. 2010).
AX J163904–4642 Originally identified as a 912s pulsating, heavily-absorbed, HMXB (Bodaghee et al. 2006; Thompson et al.
2006), this source has now been reclassified as a SyXB (Nespoli et al. 2010).
AX J164042–4632 X-ray PWN associated with the radio SNR G338.3–0.0 and the very high energy γ-ray source HESS J1640–
465 (Funk et al. 2007; Lemiere et al. 2009). This system is also associated with the Fermi-LAT source 1FGL J1640.8–4634
(Abdo et al. 2010; Slane et al. 2010).
AX J165437–4333 The F7V type star HD 152335 (Sugizaki et al. 2001).
AX J165904–4242 Herbig Be star V921 Sco, where the X-ray emission may arise from magnetic activity (Hamaguchi et al.
2005). (Sugizaki et al. 2001, incorrectly assigned this star as the counterpart to AX J165901–4208.)
AX J170006–4157 Magnetized CV, likely of the IP class, with 715s X-ray pulsations (Torii et al. 1999; Kaur et al. 2010).
AX J170047–4139 38s pulsating HMXB with an Ofpe/WNL type mass donor (Chakrabarty et al. 2002; Mason et al. 2009).
AX J170349–4142 SNR G344.7–0.1 and its possible central compact object (CCO; Combi et al. 2010). There is a possible γ-ray
counterpart, HESS J1702–420 (Giacani et al. 2011).
AX J171804–3726 SNR G349.7+0.2 and its possible CCO (Slane et al. 2002; Lazendic et al. 2005). This remnant is also
associated with the Fermi-LAT source 1FGL J1717.9–3729 (Castro & Slane 2010).
AX J172105–3726 SNR G350.1–0.3 and its CCO (Gaensler et al. 2008; Lovchinsky et al. 2011).
T HE C H I C AGO S URVEY
25
AX J172743–3506 SNR G352.7–0.1 (Giacani et al. 2009).
AX J173441–3234 Colliding-wind binary (CWB) HD 159176 (07V+07V) in the young open cluster NGC 6383. The short
period of this binary implies that the winds likely collide well before reaching their terminal velocities, limiting the hardness
of the resulting thermal X-ray emission (De Becker et al. 2004).
AX J173518–3237 SNR G355.6–0.0 (Yamauchi et al. 2008).
AX J180225–2300 X-ray emission associated with the OB type and pre-main-sequence stars in the Trifid Nebula. The main
X-ray contributor is the HD 164492 multiple system of OB stars (Rho et al. 2004).
AX J180838–2024 Magnetar SGR 1806–20 (Kouveliotou et al. 1998).
AX J180902–1948 SNR G10.5–0.0. Other than this ASCA detection (Sugizaki et al. 2001), no other X-ray papers exist on this
source. The radio SNR was discovered by Brogan et al. (2006).
AX J180948–1918 PSR J1809–1917 and its PWN, which are likely associated with HESS J1809–193 (Kargaltsev & Pavlov
2007; Aharonian et al. 2007).
AX J180951–1943 The X-ray and radio emitting magnetar XTE J1810–197 (Ibrahim et al. 2004; Halpern et al. 2005).
AX J181211–1835 SNR G12.0–0.1 (Yamauchi et al. 2008).
AX J182104–1420 SNR G16.7+0.1 and its central PWN (Helfand et al. 2003a).
AX J183039–1002 A Compton-thick active galactic nucleus (Bassani et al. 2009). A Ks -band magnitude of 14.3 ± 0.2 was
obtained for this source with PANIC on 2007 July 29 (see Section 4.3.15).
AX J183221–0840 Magnetized CV, likely of the IP class, with 1549.1s X-ray period pulsations (Sugizaki et al. 2000; Kaur et al.
2010).
AX J183528–0737 The 112s pulse period X-ray binary, Scutum X-1. This system is likely to be a SyXB (Kaplan et al. 2007).
AX J183800–0655 The 70.5 ms pulsar, PSR J1838–0655, and its PWN. This system is possibly associated with HESS J1837–
069 (Gotthelf & Halpern 2008; Kargaltsev et al. 2012).
AX J183931–0544 The luminous blue variable (LBV) candidate G26.47+0.02. This source is possibly in a CWB (Paron et al.
2012). It is assumed that the 2MASS J18393224–0544204 is the correct NIR counterpart for the purpose of the statistical
analysis in Section 4.4.
AX J184121–0455 The magnetar 1E 1841–045 and its associated SNR G27.4+0.0 (Kes 73; Gotthelf & Vasisht 1997; Morii et al.
2003).
AX J184355–0351 X-ray emission associated with the non-thermal SNR G28.6–0.1/AX J1843.8–0352 and the thermal source
CXO J184357–035441 (which may or may not be part of SNR G28.6–0.1, Bamba et al. 2001; Ueno et al. 2003).
AX J184629–0258 X-ray emission from the SNR G29.7–0.3 (Kes 75), its central pulsar PSR J1846–0258 and associated PWN
(Helfand et al. 2003b).
AX J184848–0129 X-ray sources in the Galactic globular cluster GLIMPSE–C01 (Pooley et al. 2007) and the nearby diffuse
source CXOU J184846.3–013040 (either a PWN or the globular cluster’s bow shock; Mirabal 2010). These sources may
also be associated with the Fermi-LAT source 0FGL J1848.6–0138 (Luque-Escamilla et al. 2009).
AX J184930–0055 X-ray emission associated with the thermal composite SNR G31.9+0.0 (3C 391; Chen & Slane 2001; Chen
et al. 2004). This SNR is likely associated with 1FGL J1849.0–0055 (Castro & Slane 2010).
AX J185015–0025 The X-ray synchrotron-dominated SNR G32.4+0.1 (Yamaguchi et al. 2004).
AX J185240+0038 X-ray emission associated with the SNR G33.6+0.1 (Kes 79) and the 105 ms pulsar PSR J1852+0040 (there
is no detectable PWN; Gotthelf & Halpern 2005). This pulsar has been described as an “anti-magnetar” (Halpern &
Gotthelf 2010).
AX J185551+0129 X-ray emission from SNR G34.7–0.4 (also known as W44 and 3C392) and the PWN associated with its
central pulsar, PSR B1853+0.1 (Petre et al. 2002). This system may be associated with the Fermi-LAT source 0FGL
J1855.9+0126/1FGL 1856.1+0122 (Abdo et al. 2009, 2010).
AX J190734+0709 SNR G41.1–0.3 (3C 397; Safi-Harb et al. 2005).
AX J191105+0906 SNR G43.3–0.2 (W49B; Hwang et al. 2000).
AX J194649+2512 X-ray emission likely associated with the Hα emission line star VES 52 (Kohoutek & Wehmeyer 1997;
Sugizaki et al. 2001, this identification still needs to be properly confirmed by follow-up X-ray observations).
26
CHANDRA DETECTED X-RAY POINT SOURCES BEYOND THE 30 SEARCH REGION
Table 13 lists those 14 Chandra detected X-ray point sources with > 20 X-ray counts that lie within 30 − 50 of the ASCA position
of 11 AGPS sources and therefore outside the ChIcAGO MAP default search radius. This Table includes the name of the AGPS
sources for which the above applies, the position of the X-ray source, the offset from the original ASCA position, the net number
of counts, and the most likely 2MASS counterpart.
A thorough analysis of these 14 X-ray point sources is beyond the scope of this paper, however, we have done a preliminary
investigation of their possible contribution to the fluxes originally measured in the AGPS (Sugizaki et al. 2001). Using a similar
technique to that described in Section 2.1 we entered the power law spectral fit of the AGPS source measured by Sugizaki et al.
(2001) into Chandra PIMMS in order to estimate the number of source counts expected to be detected in the corresponding
ChIcAGO Chandra observation. (Once again the photon index and absorption were set to Γ = 2 and NH = 1022 cm−2 if no power
law fit was provided.) These count predictions are listed in Table 13. The total number of counts detected from all the X-ray
sources within 30 of the AGPS position are also included alongside these values. In the case of AX J154557–5420, AX J154905–
5420, AX J172642–3504, AX J181915–1601, AX J184741–0129, AX J194332+2323, the total number of X-ray counts detected
within 30 of the AGPS position contribute ≤ 65% of the predicted number of counts. It is therefore possible that the 8 X-ray
point sources detected between 30 − 50 from these AGPS sources could have contributed to the X-ray flux originally detected with
ASCA. Such a result would not be unexpected for AX J154905–5420 and AX J194332+2323 as their corresponding Chandra
resolved point sources are stars in H II regions, which were not individually resolved with ASCA. This analysis demonstrates
that few X-ray sources beyond 30 of the ASCA position contributed to the overall flux of a given AGPS source. The 30 search
radius used in ChIcAGO MAP is therefore reasonable for detecting the majority of AGPS associated point sources detected with
Chandra. (Note that this Table does not include the magnetar PSR J1622–4950 that was detected in the Chandra observation of
AX J162246–4946, 40 for its ASCA position, as it was well investigated in Anderson et al. 2012).
G.E.A acknowledges the support of an Australian Postgraduate Award. B.M.G. acknowledges the support of an Australian Laureate Fellowship through ARC grant FL100100114. P.O.S. acknowledges partial support from NASA Contract NAS8-03060.
D.T.H.S. acknowledges a STFC Advanced Fellowship. J.J.D was supported by NASA contract NAS8-39073 to the Chandra
X-ray Center (CXC). Support for this work was also provided by NASA through Chandra Award Number GO9-0155X issued
by the CXC, which is operated by the Smithsonian Astrophysical Observatory for and on behalf of NASA. The access to major
research facilities program is supported by the Commonwealth of Australia under the International Science Linkages program.
This research makes use of data obtained with the Chandra X-ray Observatory, and software provided by the CXC in the application packages CIAO. The ATCA is part of the Australia Telescope, funded by the Commonwealth of Australia for operation
as a National Facility managed by CSIRO. The MOST is operated with the support of the Australian Research Council and
the Science Foundation for Physics within the University of Sydney. Observing time on the 6.5m Clay and Baade Magellan
Telescopes, located at Las Campanas Observatory, was allocated through the Harvard-Smithsonian Center for Astrophysics and
the Massachusetts Institute of Technology. 2MASS is a joint project of the University of Massachusetts and the IPAC/Caltech,
funded by the NASA and NFS. GLIMPSE survey data are part of the Spitzer Legacy Program. The Spitzer Space Telescope is
operated by JPL/Caltech under a contract with NASA. This research has made use of NASA’s Astrophysics Data System.
Facilities: ASCA, ATCA, CXO (ACIS,HRC), CTIO:2MASS, FLWO:2MASS, Magellan:Baade (IMACS, MagIC, PANIC), Molonglo, Spitzer, VLA, XMM (EPIC)
Cash, W. 1979, ApJ, 228, 939
REFERENCES
Abdo, A. A. et al.. 2010, ApJS, 188, 405
—. 2009, ApJS, 183, 46
Aharonian, F. et al.. 2007, A&A, 467, 1075
Anderson, G. E. et al.. 2011, ApJ, 727, 105
—. 2012, ApJ, 751, 53
Bamba, A., Ueno, M., Koyama, K., & Yamauchi, S. 2001, PASJ, 53, L21
Bassani, L., Landi, R., Campana, R., McBride, V. A., Dean, A. J., Bird,
A. J., Green, D. A., Ubertini, P., & de Rosa, A. 2009, MNRAS, 395, L1
Benjamin, R. A. et al.. 2003, PASP, 115, 953
Bernardini, F. et al.. 2011, A&A, 529, A19
Bertin, E. & Arnouts, S. 1996, A&AS, 117, 393
Bird, A. J. et al.. 2010, ApJS, 186, 1
—. 2007, ApJS, 170, 175
Bocchino, F., Parmar, A. N., Mereghetti, S., Orlandini, M., Santangelo, A.,
& Angelini, L. 2001, A&A, 367, 629
Bock, D. C.-J., Large, M. I., & Sadler, E. M. 1999, AJ, 117, 1578
Bodaghee, A., Walter, R., Zurita Heras, J. A., Bird, A. J., Courvoisier,
T. J.-L., Malizia, A., Terrier, R., & Ubertini, P. 2006, A&A, 447, 1027
Brogan, C. L., Gelfand, J. D., Gaensler, B. M., Kassim, N. E., & Lazio,
T. J. W. 2006, ApJ, 639, L25
Broos, P. S., Feigelson, E. D., Townsley, L. K., Getman, K. V., Wang, J.,
Garmire, G. P., Jiang, Z., & Tsuboi, Y. 2007, ApJS, 169, 353
Buccheri, R. et al.. 1983, A&A, 128, 245
Busfield, A. L., Purcell, C. R., Hoare, M. G., Lumsden, S. L., Moore,
T. J. T., & Oudmaijer, R. D. 2006, MNRAS, 366, 1096
Castro, D. & Slane, P. 2010, ApJ, 717, 372
Caswell, J. L., Clark, D. H., Crawford, D. F., & Green, A. J. 1975,
Australian Journal of Physics Astrophysical Supplement, 37, 1
Caswell, J. L. & Haynes, R. F. 1987, A&A, 171, 261
Chakrabarty, D., Wang, Z., Juett, A. M., Lee, J. C., & Roche, P. 2002, ApJ,
573, 789
Chen, Y. & Slane, P. O. 2001, ApJ, 563, 202
Chen, Y., Su, Y., Slane, P. O., & Wang, Q. D. 2004, ApJ, 616, 885
Churchwell, E. et al.. 2006, ApJ, 649, 759
Churchwell, E., Watson, D. F., Povich, M. S., Taylor, M. G., Babler, B. L.,
Meade, M. R., Benjamin, R. A., Indebetouw, R., & Whitney, B. A. 2007,
ApJ, 670, 428
Combi, J. A. et al.. 2010, A&A, 522, A50
Combi, J. A., Albacete Colombo, J. F., Romero, G. E., & Benaglia, P. 2006,
ApJ, 653, L41
Condon, J. J., Cotton, W. D., Greisen, E. W., Yin, Q. F., Perley, R. A.,
Taylor, G. B., & Broderick, J. J. 1998, AJ, 115, 1693
Crowther, P. A., Smith, L. J., Hillier, D. J., & Schmutz, W. 1995, A&A, 293,
427
Davis, J. E. 2001, ApJ, 562, 575
De Becker, M., Rauw, G., Pittard, J. M., Antokhin, I. I., Stevens, I. R.,
Gosset, E., & Owocki, S. P. 2004, A&A, 416, 221
Degenaar, N. et al.. 2012, A&A, 540, A22
Dickey, J. M. & Lockman, F. J. 1990, ARA&A, 28, 215
T HE C H I C AGO S URVEY
Dorman, B. & Arnaud, K. A. 2001, in Astronomical Data Analysis Software
and Systems X, ed. F. R. Harnden, F. A. Primini Jr, & H. E. Payne (San
Francisco: Astronomical Society of the Pacific), p. 415
Draper, P. W., Berry, D. S., Jenness, T., & Economou, F. 2009, in ASP Conf.
Ser. Astronomical Data Analysis Software and Systems XVIII, ed. D. A.
Bohlender, D. Durand, & P. Dowler, Vol. 411 (San Francisco:
Astronomical Society of the Pacific), 575
Dressler, A., Hare, T., Bigelow, B. C., & Osip, D. J. 2006, Proc. SPIE, 6269,
13
Drew, J. E. et al.. 2005, MNRAS, 362, 753
Durant, M. & van Kerkwijk, M. H. 2005, ApJ, 627, 376
Ebeling, H. & Wiedenmann, G. 1993, Phys. Rev. E, 47, 704
Ebisawa, K. et al.. 2005, ApJ, 635, 214
Evans, I. N. et al.. 2010, ApJS, 189, 37
Favata, F., Flaccomio, E., Reale, F., Micela, G., Sciortino, S., Shang, H.,
Stassun, K. G., & Feigelson, E. D. 2005, ApJS, 160, 469
Fich, M. & Blitz, L. 1984, ApJ, 279, 125
Freeman, P. E., Kashyap, V., Rosner, R., & Lamb, D. Q. 2002, ApJS, 138,
185
Funk, S., Hinton, J. A., Pühlhofer, G., Aharonian, F. A., Hofmann, W.,
Reimer, O., & Wagner, S. 2007, ApJ, 662, 517
Gaensler, B. M. & Hunstead, R. W. 2000, PASA, 17, 72
Gaensler, B. M., Tanna, A., Slane, P. O., Brogan, C. L., Gelfand, J. D.,
McClure-Griffiths, N. M., Camilo, F., Ng, C.-Y., & Miller, J. M. 2008,
ApJ, 680, L37
Garmire, G. P., Bautz, M. W., Ford, P. G., Nousek, J. A., & Ricker, Jr., G. R.
2003, Proc. SPIE, 4851, 28
Gehrels, N. 1986, ApJ, 303, 336
Gehrels, N. et al.. 2004, ApJ, 611, 1005
Gelfand, J. D. & Gaensler, B. M. 2007, ApJ, 667, 1111
Getman, K. V. et al.. 2005, ApJS, 160, 319
Giacani, E., Smith, M. J. S., Dubner, G., & Loiseau, N. 2011, A&A, 531,
A138
Giacani, E., Smith, M. J. S., Dubner, G., Loiseau, N., Castelletti, G., &
Paron, S. 2009, A&A, 507, 841
Gotthelf, E. V. & Halpern, J. P. 2005, ApJ, 632, 1075
—. 2007, Ap&SS, 308, 79
—. 2008, ApJ, 681, 515
Gotthelf, E. V. & Vasisht, G. 1997, ApJ, 486, L133
Green, A. J., Cram, L. E., Large, M. I., & Ye, T. 1999, ApJS, 122, 207
Green, D. A. 2009, Bulletin of the Astronomical Society of India, 37, 45
Grindlay, J. E. et al.. 2005, ApJ, 635, 920
Haberl, F., Eger, P., & Pietsch, W. 2008, A&A, 489, 327
Hadfield, L. J., van Dyk, S. D., Morris, P. W., Smith, J. D., Marston, A. P., &
Peterson, D. E. 2007, MNRAS, 376, 248
Halpern, J. P. & Gotthelf, E. V. 2010, ApJ, 710, 941
Halpern, J. P., Gotthelf, E. V., Becker, R. H., Helfand, D. J., & White, R. L.
2005, ApJ, 632, L29
Hamaguchi, K., Yamauchi, S., & Koyama, K. 2005, ApJ, 618, 360
Hands, A. D. P., Warwick, R. S., Watson, M. G., & Helfand, D. J. 2004,
MNRAS, 351, 31
Haverkorn, M., Gaensler, B. M., McClure-Griffiths, N. M., Dickey, J. M., &
Green, A. J. 2006, ApJS, 167, 230
Helfand, D. J., Agüeros, M. A., & Gotthelf, E. V. 2003a, ApJ, 592, 941
Helfand, D. J., Becker, R. H., White, R. L., Fallon, A., & Tuttle, S. 2006, AJ,
131, 2525
Helfand, D. J., Collins, B. F., & Gotthelf, E. V. 2003b, ApJ, 582, 783
Helfand, D. J., Velusamy, T., Becker, R. H., & Lockman, F. J. 1989, ApJ,
341, 151
Hong, J. 2012, MNRAS, 427, 1633
Hong, J., Schlegel, E. M., & Grindlay, J. E. 2004, ApJ, 614, 508
Hong, J., van den Berg, M., Schlegel, E. M., Grindlay, J. E., Koenig, X.,
Laycock, S., & Zhao, P. 2005, ApJ, 635, 907
Hong, J. S., van den Berg, M., Laycock, S., Grindlay, J. E., & Zhao, P. 2009,
ApJ, 699, 1053
Hwang, U., Petre, R., & Hughes, J. P. 2000, ApJ, 532, 970
Ibrahim, A. I. et al.. 2004, ApJ, 609, L21
Israel, G. et al.. 2005, A&A, 438, L1
Israel, G. L. et al.. 2004, ApJ, 603, L97
—. 2009, The Astronomer’s Telegram, 1909
Jannuzi, B. T. et al.. 2004, BAAS, 36, 1478
Kaastra, J. S. 1992, in An X-ray Spectral Code for Optically Thin Plasmas
Updated Version 2.0 (Leidon: SRON)
Kalberla, P. M. W., Burton, W. B., Hartmann, D., Arnal, E. M., Bajaja, E.,
Morras, R., & Pöppel, W. G. L. 2005, A&A, 440, 775
Kaplan, D. L., Frail, D. A., Gaensler, B. M., Gotthelf, E. V., Kulkarni, S. R.,
Slane, P. O., & Nechita, A. 2004, ApJS, 153, 269
27
Kaplan, D. L., Levine, A. M., Chakrabarty, D., Morgan, E. H., Erb, D. K.,
Gaensler, B. M., Moon, D.-S., & Cameron, P. B. 2007, ApJ, 661, 437
Kargaltsev, O. & Pavlov, G. G. 2007, ApJ, 670, 655
Kargaltsev, O., Schmitt, B. M., Pavlov, G. G., & Misanovic, Z. 2012, ApJ,
745, 99
Kashyap, V. L., van Dyk, D. A., Connors, A., Freeman, P. E.,
Siemiginowska, A., Xu, J., & Zezas, A. 2010, ApJ, 719, 900
Kaur, R., Wijnands, R., Paul, B., Patruno, A., & Degenaar, N. 2010,
MNRAS, 402, 2388
Kenter, A. et al.. 2005, ApJS, 161, 9
Kohoutek, L. & Wehmeyer, R. 1997, Astronomische Abhandlungen der
Hamburger Sternwarte, 11, 1
Kouveliotou, C. et al.. 1998, Nature, 393, 235
Krivonos, R., Revnivtsev, M., Lutovinov, A., Sazonov, S., Churazov, E., &
Sunyaev, R. 2007, A&A, 475, 775
Kuchar, T. A. & Bania, T. M. 1994, ApJ, 436, 117
Kuchar, T. A. & Clark, F. O. 1997, ApJ, 488, 224
Lazendic, J. S., Slane, P. O., Hughes, J. P., Chen, Y., & Dame, T. M. 2005,
ApJ, 618, 733
Lemiere, A., Slane, P., Gaensler, B. M., & Murray, S. 2009, ApJ, 706, 1269
Levin, L. et al.. 2010, ApJ, 721, L33
Liedahl, D. A., Osterheld, A. L., & Goldstein, W. H. 1995, ApJ, 438, L115
Liu, Q. Z., van Paradijs, J., & van den Heuvel, E. P. J. 2006, A&A, 455, 1165
Lovchinsky, I., Slane, P., Gaensler, B. M., Hughes, J. P., Ng, C.-Y.,
Lazendic, J. S., Gelfand, J. D., & Brogan, C. L. 2011, ApJ, 731, 70
Lucy, L. B. 1982, ApJ, 255, 286
Lucy, L. B. & White, R. L. 1980, ApJ, 241, 300
Luque-Escamilla, P. L., Martí, J., Muñoz-Arjonilla, A. J., Sánchez-Sutil,
J. R., Combi, J. A., & Sánchez-Ayaso, E. 2009, A&A, 508, 1095
Maercker, M. & Burton, M. G. 2005, A&A, 438, 663
Maercker, M., Burton, M. G., & Wright, C. M. 2006, A&A, 450, 253
Mainieri, V., Bergeron, J., Hasinger, G., Lehmann, I., Rosati, P., Schmidt,
M., Szokoly, G., & Della Ceca, R. 2002, A&A, 393, 425
Manchester, R. N., Hobbs, G. B., Teoh, A., & Hobbs, M. 2005, AJ, 129,
1993
Markwardt, C. B., Baumgartner, W. H., Skinner, G. K., & Corbet, R. H. D.
2010, The Astronomer’s Telegram, 2564
Martini, P., Persson, S. E., Murphy, D. C., Birk, C., Shectman, S. A.,
Gunnels, S. M., & Koch, E. 2004, Proc. SPIE, 5492, 1653
Masetti, N. et al.. 2007, A&A, 470, 331
Mason, A. B., Clark, J. S., Norton, A. J., Negueruela, I., & Roche, P. 2009,
A&A, 505, 281
Mateos, S. et al.. 2008, A&A, 492, 51
Mauerhan, J. C., Muno, M. P., Morris, M. R., Stolovy, S. R., & Cotera, A.
2010, ApJ, 710, 706
Mauerhan, J. C., Van Dyk, S. D., & Morris, P. W. 2011, AJ, 142, 40
McClintock, J. E. & Remillard, R. A. 2006, in Compact stellar X-ray
sources, ed. W. H. G. Lewin & M. van der Klis (Cambridge: Cambridge
Univ. Press), p. 157
McClure-Griffiths, N. M., Green, A. J., Dickey, J. M., Gaensler, B. M.,
Haynes, R. F., & Wieringa, M. H. 2001, ApJ, 551, 394
McLean, B. J., Greene, G. R., Lattanzi, M. G., & Pirenne, B. 2000, in ASP
Conf. Ser. Astronomical Data Analysis Software and Systems IX, ed.
N. Manset, C. Veillet, & D. Crabtree, Vol. 216 (San Francisco:
Astronomical Society of the Pacific), 145
Mereghetti, S., Esposito, P., Tiengo, A., Götz, D., Israel, G. L., & De Luca,
A. 2012, A&A, 546, A30
Mereghetti, S. et al.. 2005, ApJ, 628, 938
Mewe, R., Gronenschild, E. H. B. M., & van den Oord, G. H. J. 1985,
A&AS, 62, 197
Mewe, R., Lemen, J. R., & van den Oord, G. H. J. 1986, A&AS, 65, 511
Mirabal, N. 2010, MNRAS, 402, 1391
Monet, D. G. et al.. 2003, AJ, 125, 984
Morii, M., Sato, R., Kataoka, J., & Kawai, N. 2003, PASJ, 55, L45
Motch, C., Guillout, P., Haberl, F., Krautter, J., Pakull, M. W., Pietsch, W.,
Reinsch, K., Voges, W., & Zickgraf, F.-J. 1998, A&AS, 132, 341
Motch, C., Guillout, P., Haberl, F., Pakull, M., Pietsch, W., & Reinsch, K.
1997, A&A, 318, 111
Motch, C. et al.. 2010, A&A, 523, A92
Muno, M. P., Baganoff, F. K., Bautz, M. W., Brandt, W. N., Garmire, G. P.,
& Ricker, G. R. 2003, ApJ, 599, 465
Murphy, T., Mauch, T., Green, A., Hunstead, R. W., Piestrzynska, B., Kels,
A. P., & Sztajer, P. 2007, MNRAS, 382, 382
Murray, S. S. 2000, American Physical Society April Meeting, Abstract
J8.003
Nazé, Y., Rauw, G., & Manfroid, J. 2008, A&A, 483, 171
Nazé, Y., Zhekov, S. A., & Walborn, N. R. 2012, ApJ, 746, 142
28
Negueruela, I. & Schurch, M. P. E. 2007, A&A, 461, 631
Nespoli, E., Fabregat, J., & Mennickent, R. E. 2010, A&A, 516, A94
Ohashi, T. et al.. 1996, PASJ, 48, 157
Osip, D. J., Floyd, D., & Covarrubias, R. 2008, Proc. SPIE, 7014, 70140A
Oskinova, L. M. 2005, MNRAS, 361, 679
Paron, S., Combi, J. A., Petriella, A., & Giacani, E. 2012, A&A, 543, A23
Pavan, L., Bozzo, E., Ferrigno, C., Ricci, C., Manousakis, A., Walter, R., &
Stella, L. 2011, A&A, 526, A122
Peretto, N. & Fuller, G. A. 2009, A&A, 505, 405
Petre, R., Kuntz, K. D., & Shelton, R. L. 2002, ApJ, 579, 404
Pooley, D., Rappaport, S., Levine, A., Pfahl, E., & Schwab, J. 2007,
arXiv:astro-ph/0708.3365
Ramos-Larios, G., Phillips, J. P., & Pérez-Grana, J. A. 2010, MNRAS, 405,
245
Reig, P. 2011, Ap&SS, 332, 1
Rho, J., Ramírez, S. V., Corcoran, M. F., Hamaguchi, K., & Lefloch, B.
2004, ApJ, 607, 904
Rodriguez, J. et al.. 2006, MNRAS, 366, 274
Russeil, D. 2003, A&A, 397, 133
Safi-Harb, S., Dubner, G., Petre, R., Holt, S. S., & Durouchoux, P. 2005,
ApJ, 618, 321
Sana, H., Rauw, G., Nazé, Y., Gosset, E., & Vreux, J. 2006, MNRAS, 372,
661
Sguera, V. et al.. 2006, ApJ, 646, 452
Shaver, P. A. & Goss, W. M. 1970, Australian Journal of Physics
Astrophysical Supplement, 14, 133
Simpson, J. P. & Cotera, A. S. 2004, BAAS, 36, 734
Skrutskie, M. F. et al.. 2006, AJ, 131, 1163
Slane, P., Castro, D., Funk, S., Uchiyama, Y., Lemiere, A., Gelfand, J. D., &
Lemoine-Goumard, M. 2010, ApJ, 720, 266
Slane, P., Chen, Y., Lazendic, J. S., & Hughes, J. P. 2002, ApJ, 580, 904
Smith, D. A. et al.. 2008, A&A, 492, 923
Stetson, P. B. 2000, PASP, 112, 925
Stil, J. M., Taylor, A. R., Dickey, J. M., Kavars, D. W., Martin, P. G.,
Rothwell, T. A., Boothroyd, A. I., Lockman, F. J., & McClure-Griffiths,
N. M. 2006, AJ, 132, 1158
Sugizaki, M., Kinugasa, K., Matsuzaki, K., Terada, Y., Yamauchi, S., &
Yokogawa, J. 2000, ApJ, 534, L181
Sugizaki, M., Mitsuda, K., Kaneda, H., Matsuzaki, K., Yamauchi, S., &
Koyama, K. 2001, ApJS, 134, 77
Thompson, T. W. J., Tomsick, J. A., Rothschild, R. E., in’t Zand, J. J. M., &
Walter, R. 2006, ApJ, 649, 373
Tody, D. 1986, Proc. SPIE, 627, 733
Tody, D. 1993, in ASP Conf. Ser. Astronomical Data Analysis Software and
Systems II, ed. R. J. Hanisch, R. J. V. Brissenden, & J. Barnes, Vol. 52
(San Francisco: Astronomical Society of the Pacific), 173
Tomsick, J. A., Chaty, S., Rodriguez, J., Foschini, L., Walter, R., & Kaaret,
P. 2006, ApJ, 647, 1309
Torii, K., Sugizaki, M., Kohmura, T., Endo, T., & Nagase, F. 1999, ApJ, 523,
L65
Torres, C. A. O., Quast, G. R., da Silva, L., de La Reza, R., Melo, C. H. F.,
& Sterzik, M. 2006, A&A, 460, 695
Ueno, M., Bamba, A., Koyama, K., & Ebisawa, K. 2003, ApJ, 588, 338
Usov, V. V. 1992, ApJ, 389, 635
van den Berg, M., Penner, K., Hong, J., Grindlay, J. E., Zhao, P., Laycock,
S., & Servillat, M. 2012, ApJ, 748, 31
Voges, W. et al.. 1999, A&A, 349, 389
Vogt, N. & Bateson, F. M. 1982, A&AS, 48, 383
Walborn, N. R. 1973, AJ, 78, 1067
Walter, R. et al.. 2006, A&A, 453, 133
Watson, M. G. et al.. 2009, A&A, 493, 339
Weisskopf, M. C., Aldcroft, T. L., Bautz, M., Cameron, R. A., Dewey, D.,
Drake, J. J., Grant, C. E., Marshall, H. L., & Murray, S. S. 2003,
Experimental Astronomy, 16, 1
Weisskopf, M. C., Wu, K., Trimble, V., O’Dell, S. L., Elsner, R. F., Zavlin,
V. E., & Kouveliotou, C. 2007, ApJ, 657, 1026
Whiteoak, J. B. Z. & Green, A. J. 1996, A&AS, 118, 329
Wolk, S. J., Harnden, Jr., F. R., Flaccomio, E., Micela, G., Favata, F., Shang,
H., & Feigelson, E. D. 2005, ApJS, 160, 423
Yamaguchi, H., Ueno, M., Koyama, K., Bamba, A., & Yamauchi, S. 2004,
PASJ, 56, 1059
Yamauchi, S., Bamba, A., & Koyama, K. 2011, PASJ, 63, 957
Yamauchi, S., Ueno, M., Koyama, K., & Bamba, A. 2008, PASJ, 60, 1143
Zhao, P., Grindlay, J. E., Hong, J. S., Laycock, S., Koenig, X. P., Schlegel,
E. M., & van den Berg, M. 2005, ApJS, 161, 429
Zolotukhin, I. Y. & Chilingarian, I. V. 2011, A&A, 526, A84
Source ID
ChI
(ID, Date,
Inst, Exp)
RA
(J2000)
Dec
(J2000)
wavdetect Position
AX J143148-6021 8239 2007-09-05 ACIS-S 2.62ks
J143148-6021_1
14:31:50.18 −60:22:08.3
J143148-6021_2
14:31:48.56 −60:21:44.5
J143148-6021_3
14:31:48.06 −60:19:59.5
J143148-6021_4
14:31:41.52 −60:19:55.2
J143148-6021_5
14:32:02.80 −60:18:57.4
AX J144042-6001 9599 2008-05-04 HRC-I 1.18ks
J144042-6001_1
14:40:38.40 −60:01:36.8
AX J144519-5949 8235 2007-10-19 ACIS-S 1.75ks
J144519-5949_1
14:45:15.08 −59:49:29.1
J144519-5949_2
14:45:21.39 −59:49:25.3
J144519-5949_3
14:45:12.73 −59:48:38.4
J144519-5949_4
14:45:19.31 −59:48:00.7
J144519-5949_5
14:44:57.87 −59:50:39.0
J144519-5949_6
14:45:05.79 −59:49:32.2
AX J144547-5931 8240 2007-08-12 ACIS-S 2.52ks
J144547-5931_1
14:45:43.67 −59:32:05.2
AX J144701-5919 8233 2007-01-13 ACIS-S 1.43ks
J144701-5919_1
14:46:53.59 −59:19:38.3
AX J145732-5901 11880 2010-05-05 ACIS-S 10.03ks
J145732-5901_1
14:57:34.93 −58:59:53.9
J145732-5901_2
14:57:42.16 −58:59:04.5
AX J150436-5824 10508 2009-06-06 ACIS-S 4.3ks
J150436-5824_1
15:04:30.99 −58:24:11.3
J150436-5824_2
15:04:31.40 −58:23:05.8
J150436-5824_3
15:04:51.09 −58:24:58.8
AX J151005-5824 11881 2010-06-14 ACIS-S 9.92ks
J151005-5824_1
15:10:15.36 −58:25:42.1
J151005-5824_2
15:09:54.87 −58:24:37.1
J151005-5824_3
15:10:07.69 −58:23:19.8
J151005-5824_4
15:10:07.13 −58:26:09.0
J151005-5824_5
15:10:06.84 −58:25:56.8
J151005-5824_6
15:09:51.83 −58:25:03.1
J151005-5824_7
15:10:11.48 −58:23:36.7
J151005-5824_8
15:10:03.45 −58:26:45.6
J151005-5824_9
15:09:55.60 −58:26:22.0
J151005-5824_10 15:09:52.35 −58:27:12.2
J151005-5824_11 15:10:05.09 −58:26:02.1
AX J153751-5556 10509 2009-01-24 ACIS-S 4.49ks
J153751-5556_1†
15:37:59.32 −55:54:23.3
J153751-5556_2
15:37:35.15 −55:56:50.1
AX J153818-5541 9600 2008-05-24 HRC-I 1.16ks
J153818-5541_1
15:38:14.00 −55:42:13.6
AX J154122-5522 8238 2007-06-21 ACIS-S 1.93ks
J154122-5522_1
15:41:15.79 −55:21:28.7
ChIcAGOb
Chandra Obsa
0.6
0.5
0.3
0.6
0.7
0.3
0.7
0.4
0.5
0.8
1.0
0.8
0.3
0.3
0.4
0.8
0.3
0.8
0.6
0.6
0.6
0.7
0.6
0.5
0.6
0.4
0.6
0.8
0.9
0.6
0.5
0.9
0.4
0.3
0.56
0.61
0.47
1.42
1.79
2.81
1.71
0.46
1.04
1.45
2.56
0.89
1.75
1.93
1.49
1.45
1.59
1.26
1.06
1.83
1.49
1.88
1.98
2.90
1.14
2.16
2.40
1.02
1.05
wav
(00 )
0.8
0.8
0.9
1.1
0.9
0.9
1.0
0.9
0.9
0.9
0.8
0.9
1.0
1.1
0.9
0.8
1.1
0.9
0.8
1.1
0.8
0.8
1.0
0.8
0.8
1.1
1.2
1.1
0.8
0.9
0.8
0.8
0.9
1.0
Total
(00 )
Positional Errorsd
0.97
0.56
1.19
1.56
2.81
from
ASCA (0 )
Offsetc
36+7
−6
16+5
−4
0.0+1.9
−0.0
36+7
−6
5.0+3.4
−2.2
8.0+4.0
−2.8
1.0+2.3
−0.9
1.0+2.3
−0.9
7.0+3.8
−2.6
1.9+2.7
−1.3
1.7+2.7
−1.2
9.0+4.1
−3.0
0.0+1.9
−0.0
0.0+1.9
−0.0
4.9+3.4
−2.2
0.8+2.3
−0.7
1.9+2.7
−1.3
11+4
−3
6.0+3.6
−2.4
81+10
−9
19+5
−4
5.9+3.6
−2.4
141+13
−12
4.8+3.4
−2.1
7.8+4.0
−2.7
6.9+3.8
−2.6
6.8+3.8
−2.6
6.6+3.8
−2.5
5.5+3.6
−2.3
5.3+3.6
−2.2
11+4
−3
16+5
−4
7.9+4.0
−2.8
+3.4
4.7−2.1
6.3+3.8
−2.5
4.6+3.4
−2.1
13+5
−4
5.8+3.6
−2.3
83+10
−9
65+9
−8
31+7
−6
69+9
−8
49+8
−7
2.0+2.7
−1.3
4.0+3.2
−1.9
0.0+1.9
−0.0
4.0+3.2
−1.9
3.0+2.9
−1.7
1.0+2.3
−0.8
4.0+3.2
−1.9
7.0+3.8
−2.6
51+8
−7
2.9+2.9
−1.6
+1.9
0.0−0.0
0.5-2
3.0+2.9
−1.7
27+6
−5
13+5
−4
+3.2
4.0−1.9
7.0+3.8
−2.6
3.0+2.9
−1.6
326+19
−18
4.0+3.2
−1.9
10+4
−3
146+13
−12
+3.6
5.9−2.4
+6
20−4
0.3-8
1.9 ± 0.4
2.1 ± 0.4
1.1 ± 0.1
2.2 ± 0.8
1.9 ± 0.5
1.1 ± 0.4
2.0 ± 0.4
1.0 ± 0.4
0.9 ± 0.4
2.1 ± 0.9
1.8 ± 0.2
2.3 ± 0.2
1.1 ± 0.3
0.9 ± 0.5
0.9 ± 0.3
1.6 ± 0.8
1.5 ± 0.1
4.8 ± 0.8
3.7 ± 0.2
1.1 ± 0.1
2.8 ± 0.6
4.0 ± 1.5
1.2 ± 0.2
3.8 ± 1.2
3.5 ± 1.4
1.4 ± 0.2
4.9 ± 0.7
2.9 ± 0.2
1.4 ± 0.4
2.9 ± 1.2
2.0 ± 1.6
0.8 ± 0.1
2.8+2.9
−1.6
5.9+3.6
−2.4
5.9+3.6
−2.4
5.8+3.6
−2.4
0.0+1.9
−0.0
3.7+3.2
−1.9
3.6+3.2
−1.8
1.8+2.7
−1.2
16+5
−4
7.9+4.0
−2.8
+1.9
0.0−0.0
5.6+3.6
−2.3
2.7+2.9
−1.6
0.0+1.9
−0.0
0.0+1.9
−0.0
16+5
−4
1.2 ± 0.1
1.7 ± 0.2
2.3 ± 0.1
45+8
−7
1.2 ± 0.1
1.8 ± 0.1
2.3 ± 0.2
38+7
−6
104+11
−10
0.0+1.9
−0.0
0.0+1.9
−0.0
1.1 ± 0.4
1.7 ± 0.5
1.4 ± 0.9
1.1 ± 0.1
0.5 ± 0.4
1.8 ± 0.2
Quartile
Ratio
1.7 ± 0.3
2.1 ± 0.3
1.1 ± 0.4
2.7 ± 0.2
0.6 ± 0.3
4.4 ± 0.5
E50
(keV)
Energy Quantilesf
2.8 ± 0.3
3.8 ± 0.4
1.0+2.3
−0.9
23+6
−5
13+5
−4
+1.9
0.0−0.0
4.0+3.2
−1.9
2.0+2.7
−1.3
0.0+1.9
−0.0
2.0+2.7
−1.3
95+11
−10
0.0+1.9
−0.0
20+6
−4
2-8 keV
Net Countse
Table 1
ChIcAGO MAP X-ray Results, including the position, position errors, net counts and
quantile analysis values for each ChIcAGO source
154115.7-552128
153813.9-554213
144653.5-591938
144543.6-593205
144521.3-594925
144512.7-594838
144038.4-600136
143202.8-601857
143148.0-601959
Name
CXO J
CSCg
Name
2XMMi
XMMi-DR3h
T HE C H I C AGO S URVEY
29
Source ID
ChI
(ID, Date,
Inst, Exp)
RA
(J2000)
0.8
0.8
0.4
0.5
0.4
0.5
0.6
0.5
0.9
0.6
0.7
0.9
0.6
0.6
0.7
0.5
0.6
0.6
1.1
0.5
0.4
0.5
0.4
0.3
0.3
0.8
0.3
0.7
0.3
0.4
0.3
0.4
0.7
0.6
0.8
0.4
0.8
1.27
1.97
2.07
0.90
0.49
0.59
2.43
1.61
2.63
2.30
1.02
2.15
1.61
1.52
1.20
1.37
2.88
1.66
0.12
2.41
0.63
1.37
1.03
0.90
0.67
2.47
0.80
1.00
0.65
0.38
0.22
0.76
2.00
0.80
2.17
−54:44:24.8
−54:43:28.3
−54:43:10.9
−54:42:44.8
−54:43:29.1
−54:42:39.8
−54:41:35.2
−54:21:47.7
−54:17:54.6
−54:19:12.9
−54:19:30.2
−54:22:27.7
−54:22:07.7
−54:19:54.5
−54:19:27.9
−54:19:17.0
−54:19:00.5
−54:18:53.5
−54:16:29.8
−54:09:54.3
−54:09:16.2
−54:07:21.9
−53:48:26.9
−53:47:58.6
−53:35:20.8
−53:34:06.6
−50:01:59.0
−50:01:40.8
−49:42:14.8
−50:06:00.6
−50:05:55.1
−50:04:58.4
−49:48:54.6
−49:46:37.9
−49:44:47.5
wav
(00 )
1.1
0.8
1.1
0.8
1.0
0.9
0.8
0.8
0.8
0.8
1.0
0.8
1.1
0.9
0.8
0.8
0.8
0.9
1.0
1.1
0.9
0.9
1.0
0.9
0.9
0.9
1.3
0.9
0.8
0.8
0.8
0.8
0.9
0.9
1.1
1.1
1.1
Total
(00 )
Positional Errorsd
1.77
1.82
from
ASCA (0 )
Offsetc
−55:21:12.5
−55:22:51.4
Dec
(J2000)
wavdetect Position
J154122-5522_2
15:41:33.14
J154122-5522_3
15:41:10.72
AX J154557-5443 10526 2009-06-20 ACIS-S 8.33ks
J154557-5443_1
15:45:58.23
J154557-5443_2
15:45:44.38
J154557-5443_3
15:46:12.16
J154557-5443_4
15:45:52.21
J154557-5443_5
15:45:55.39
J154557-5443_6
15:45:55.41
J154557-5443_7
15:46:10.81
AX J154905-5420 10523 2009-07-16 ACIS-S 7.6ks
J154905-5420_1
15:48:58.53
J154905-5420_2
15:49:02.83
J154905-5420_3
15:48:52.31
J154905-5420_4
15:49:04.92
J154905-5420_5
15:49:11.59
J154905-5420_6
15:49:05.63
J154905-5420_7
15:48:55.72
J154905-5420_8
15:49:09.17
J154905-5420_9
15:49:09.32
J154905-5420_10 15:48:48.45
J154905-5420_11 15:49:07.39
AX J154951-5416 10501 2009-05-15 ACIS-S 1.63ks
J154951-5416_1
15:49:51.66
AX J155035-5408 10510 2009-06-06 ACIS-S 5.37ks
J155035-5408_1
15:50:21.23
J155035-5408_2
15:50:33.73
J155035-5408_3
15:50:37.60
AX J155331-5347 8152 2007-06-21 ACIS-S 2.03ks
J155331-5347_1
15:53:36.01
J155331-5347_2
15:53:26.06
AX J155831-5334 9601 2008-04-15 ACIS-S 1.43ks
J155831-5334_1
15:58:28.38
J155831-5334_2
15:58:47.31
AX J162011-5002 9602 2008-05-28 ACIS-S 1.53ks
J162011-5002_1
16:20:06.69
J162011-5002_2
16:20:06.05
AX J162046-4942 10507 2009-01-26 ACIS-S 3.33ks
J162046-4942_1
16:20:48.82
AX J162208-5005 8141 2007-06-21 ACIS-S 1.53ks
J162208-5005_1
16:22:09.73
J162208-5005_2
16:22:08.55
J162208-5005_3
16:22:06.98
AX J162246-4946 8161 2007-06-13 ACIS-S 2.9ks
J162246-4946_1
16:22:48.03
J162246-4946_2
16:22:51.68
J162246-4946_3* 16:22:49.63
ChIcAGOb
Chandra Obsa
2.0+2.7
−1.3
0.0+1.9
−0.0
14+5
−4
3.9+3.2
−1.9
+3.4
5.0−2.2
20+6
−4
2.0+2.7
−1.3
0.9 ± 0.0
2.2 ± 0.4
1.2 ± 0.4
3.7 ± 1.0
2.0+2.7
−1.3
16+5
−4
1.4 ± 0.3
3.2 ± 0.3
4.0+3.2
−1.9
17+5
−4
3.7+3.2
−1.8
1.0 ± 0.2
4.8+3.4
−2.1
0.0+1.9
−0.0
2.0+2.7
−1.3
18+5
−4
3.9+3.2
−1.9
+3.8
7.0−2.6
1.6 ± 0.1
37+7
−6
80+10
−9
117+12
−11
1.6 ± 0.2
1.2 ± 0.8
3.7 ± 0.4
1.2 ± 0.3
47+8
−7
2.0+2.7
−1.3
6.0+3.6
−2.4
11+4
−3
53+8
−7
13+5
−4
1.1 ± 0.2
1.8 ± 0.6
1.8 ± 0.1
1.3 ± 0.2
32+7
−6
8.0+4.0
−2.8
53+8
−7
10+4
−3
1.8 ± 0.3
9.0+4.1
−3.0
3.0+2.9
−1.6
1.1 ± 0.0
60+9
−8
0.0+1.9
−0.0
71+9
−8
2.9+2.9
−1.6
1.3 ± 0.3
1.1 ± 0.2
1.5 ± 0.1
0.9 ± 0.1
3.0 ± 0.7
1.6 ± 0.1
0.0+1.9
−0.0
13+5
−4
51+8
−7
19+5
−4
5.0+3.4
−2.2
152+13
−12
21+6
−5
18+5
−4
203+15
−14
0.6 ± 0.2
2.0 ± 0.7
8.0+4.0
−2.8
8.0+4.0
−2.8
0.9 ± 0.3
1.0 ± 0.3
1.0 ± 0.5
0.7 ± 0.7
1.3 ± 0.6
2.8 ± 1.5
2.9 ± 1.5
1.3 ± 0.6
1.1 ± 1.8
1.6 ± 0.4
16+5
−4
2.0 ± 0.2
1.4 ± 0.3
2.1 ± 0.3
1.5 ± 0.4
0.7 ± 0.2
8.9+4.1
−2.9
12+5
−3
4.8+3.4
−2.1
0.0+1.9
−0.0
4.0+3.2
−1.9
3.9+3.2
−1.9
5.6+3.6
−2.3
3.9+3.2
−1.9
2.0+2.7
−1.3
0.9+2.3
−0.8
2.9+2.9
−1.6
0.0+1.9
−0.0
2.8+2.9
−1.6
0.0+1.9
−0.0
5.8+3.6
−2.4
5.9+3.6
−2.4
0.0+1.9
−0.0
2.7+2.9
−1.6
1.0+2.3
−0.8
4.0+3.2
−1.9
4.0+3.2
−1.9
8.9+4.1
−2.9
8.9+4.1
−2.9
14+5
−4
4.7+3.4
−2.1
5.4+3.6
−2.3
10+4
−3
3.9+3.2
−1.9
+4.1
8.1−2.8
4.8+3.4
−2.1
6.9+3.8
−2.6
4.8+3.4
−2.1
12+5
−3
2.9 ± 0.4
3.4 ± 0.6
3.3 ± 0.5
1.1 ± 0.2
1.5 ± 0.8
3.0+2.9
−1.6
21+6
−5
1.7+2.7
−1.2
10+4
−3
4.9+3.4
−2.1
+1.9
0.0−0.0
1.9+2.7
−1.3
23+6
−5
0.0+1.9
−0.0
20+6
−4
1.0+2.3
−0.9
0.0+1.9
−0.0
5.9+3.6
−2.4
4.0+3.2
−1.9
26+6
−5
20+6
−4
22+6
−5
11+4
−3
4.7+3.4
−2.1
+3.6
5.8−2.3
5.9+3.6
−2.4
Quartile
Ratio
1.4 ± 0.2
2.2 ± 0.3
1.8 ± 0.6
1.5 ± 0.4
2.1 ± 0.2
1.5 ± 0.4
1.9 ± 0.5
3.0+2.9
−1.7
2.0+2.7
−1.3
0.0+1.9
−0.0
4.0+3.2
−1.9
3.0+2.9
−1.6
6.0+3.6
−2.4
E50
(keV)
Energy Quantilesf
1.2 ± 0.2
4.4 ± 0.4
0.8 ± 0.1
3.9 ± 0.7
4.2 ± 0.5
0.8 ± 0.1
1.7 ± 0.3
2-8 keV
0.5-2
0.3-8
Net Countse
Table 1 — Continued
162251.6-494637
162209.7-500600
162006.7-500159
162006.0-500140
155828.3-533520
155336.0-534826
154951.6-541629
Name
CXO J
CSCg
J162048.8-494214
J155033.7-540914
J155037.5-540722
J154951.7-541630
Name
2XMMi
XMMi-DR3h
30
Source ID
ChI
(ID, Date,
Inst, Exp)
RA
(J2000)
0.6
0.9
0.3
0.6
0.9
0.6
0.5
0.3
0.3
0.3
0.3
0.6
0.3
0.4
0.3
1.0
0.4
0.5
0.5
0.5
0.7
0.3
0.6
0.4
0.6
0.3
0.4
0.3
0.6
0.5
1.65
1.22
0.88
1.51
2.60
0.75
0.89
1.34
0.28
0.55
2.64
1.01
1.61
0.85
2.58
0.96
2.38
1.65
2.95
2.69
0.25
1.93
0.98
1.72
2.00
0.48
0.85
2.13
2.02
−47:47:13.6
−47:45:06.2
−47:27:55.5
−47:27:44.6
−47:30:56.7
−47:28:31.6
−46:55:45.3
−44:02:38.8
−44:14:01.7
−43:37:43.7
−43:38:02.4
−42:38:49.4
−42:38:12.1
−42:54:42.0
−42:56:20.4
−42:07:26.0
−42:09:34.8
−42:08:45.2
−42:07:38.3
−42:05:49.0
−42:20:19.1
−42:19:00.3
−42:10:37.0
−42:13:38.0
−41:11:27.4
−41:09:19.4
−40:38:12.4
−41:04:02.7
−41:04:17.5
wav
(00 )
0.9
0.9
0.8
0.8
0.8
0.9
0.8
0.8
0.9
0.8
0.9
0.9
0.9
1.0
0.8
1.2
0.8
0.8
0.8
0.9
0.8
0.8
0.8
0.9
1.1
0.9
0.8
1.1
0.8
0.9
Total
(00 )
Positional Errorsd
2.03
from
ASCA (0 )
Offsetc
−49:46:11.1
Dec
(J2000)
wavdetect Position
J162246-4946_4
16:22:58.77
AX J163252-4746 8155 2007-10-23 HRC-I 2.64ks
J163252-4746_1
16:32:59.75
J163252-4746_2
16:32:48.55
AX J163524-4728 10519 2009-01-25 ACIS-S 6.57ks
J163524-4728_1* 16:35:20.72
J163524-4728_2* 16:35:32.89
J163524-4728_3
16:35:20.86
J163524-4728_4
16:35:20.54
AX J163751-4656 8140 2007-10-23 HRC-I 1.48ks
J163751-4656_1
16:37:50.82
AX J165105-4403 9603 2008-06-09 ACIS-S 1.84ks
J165105-4403_1
16:51:11.63
AX J165217-4414 8145 2007-10-25 ACIS-S 2.2ks
J165217-4414_1
16:52:19.02
AX J165420-433 8231 2007-10-23 HRC-I 1.56ks
J165420-4337_1
16:54:23.44
J165420-4337_2
16:54:34.86
AX J165646-4239 8241 2007-07-10 ACIS-S 2.62ks
J165646-4239_1
16:56:49.80
J165646-4239_2
16:56:50.64
AX J165707-4255 9604 2008-05-22 ACIS-S 1.24ks
J165707-4255_1
16:57:03.74
J165707-4255_2
16:57:19.97
AX J165901-4208 11882 2010-06-25 ACIS-S 9.54ks
J165901-4208_1
16:59:05.65
J165901-4208_2
16:59:11.97
J165901-4208_3†
16:59:10.07
J165901-4208_4†
16:59:17.62
J165901-4208_5
16:58:54.24
AX J165951-4209 9605 2008-06-21 ACIS-S 1.54ks
J165951-4209
No Detection
AX J170017-4220 8234 2007-09-30 ACIS-S 1.63ks
J170017-4220_1
17:00:19.29
J170017-4220_2
17:00:25.25
AX J170052-4210 8237 2007-10-25 ACIS-S 1.81ks
J170052-4210_1
17:00:58.27
AX J170112-4212 8230 2008-01-26 ACIS-S 1.28ks
J170112-4212_1
17:01:17.92
AX J170444-4109 8165 2007-10-26 ACIS-S 2.8ks
J170444-4109_1†
17:04:40.62
J170444-4109_2
17:04:42.53
AX J170536-4038 9606 2008-05-11 ACIS-S 0.94ks
J170536-4038_1
17:05:39.82
AX J170555-4104 8156 2007-10-26 ACIS-S 2.41ks
J170555-4104_1
17:05:45.50
J170555-4104_2
17:05:45.62
AX J171715-3718 9607 2008-09-20 ACIS-S 1.34ks
ChIcAGOb
Chandra Obsa
1.5 ± 0.3
1.7 ± 0.2
1.4 ± 0.1
1.5 ± 0.2
1.3 ± 0.2
1.3 ± 0.3
1.3 ± 0.4
0.9 ± 0.1
4.5 ± 0.7
1.1 ± 0.1
3.9 ± 0.6
1.2 ± 0.1
0.9 ± 0.3
1.5 ± 0.3
0.0+1.9
−0.0
8.0+4.0
−2.8
25+6
−5
21+6
−5
24+6
−5
1.0+2.3
−0.9
2.0+2.7
−1.3
34+7
−6
0.0+1.9
−0.0
122+12
−11
1.0+2.3
−0.9
89+10
−9
8.0+4.0
−2.8
10+4
−3
8.0+4.0
−2.8
148+13
−12
22+6
−5
113+12
−11
9.0+4.1
−2.9
12+5
−3
36+7
−6
1.9 ± 0.1
1.1 ± 0.4
5.1 ± 0.3
3.1 ± 0.7
65+9
−8
5.0+3.4
−2.2
1.0+2.3
−0.8
3.0+2.9
−1.6
66+9
−8
8.0+4.0
−2.8
1.7 ± 0.3
1.2 ± 0.3
1.3 ± 1.7
1.6 ± 0.3
0.9 ± 0.3
0.0+1.9
−0.0
4.0+3.2
−1.9
8.0+4.0
−2.8
0.0+1.9
−0.0
5.8+3.6
−2.4
20+6
−4
16+5
−4
8.7+4.1
−2.9
11+5
−3
10+4
−3
4.4 ± 0.4
2.6 ± 0.7
1.0 ± 0.4
4.0 ± 0.6
1.7 ± 0.8
20+6
−4
12+5
−3
0.8+2.3
−0.7
12+5
−3
4.6+3.4
−2.1
50+8
−7
5.0+3.4
−2.2
61+9
−8
5.0+3.4
−2.2
1.2 ± 0.2
6.0+3.6
−2.4
0.0+1.9
−0.0
228+16
−15
34+7
−6
265+17
−16
57+9
−8
0.9 ± 0.1
1.1 ± 0.1
2.0 ± 0.1
1.5 ± 0.1
1.1 ± 0.2
1.0 ± 0.1
2.4 ± 0.2
0.9 ± 0.3
1.4 ± 1.6
1.0 ± 0.7
1.1 ± 0.7
2.6 ± 0.9
1.2 ± 0.6
Quartile
Ratio
E50
(keV)
Energy Quantilesf
0.9 ± 0.0
1.8 ± 0.1
14+5
−4
23+6
−5
54+8
−7
53+8
−7
107+11
−10
123+12
−11
16+5
−4
94+11
−10
56+9
−7
7.7+4.0
−2.7
0.9+2.3
−0.8
0.9+2.3
−0.8
2-8 keV
150+13
−12
72+10
−8
3.6+3.2
−1.8
2.6+2.9
−1.5
13+5
−4
7.8+4.0
−2.7
4.0+3.2
−1.9
7.0+3.8
−2.6
5.0+3.4
−2.2
5.9+3.6
−2.4
4.6+3.4
−2.1
65+9
−8
0.5-2
0.3-8
Net Countse
Table 1 — Continued
170545.6-410417
170539.8-403812
170440.6-411127
170442.5-410919
170058.2-421037
170019.2-422019
165905.6-420725
165703.7-425442
165649.7-423849
165650.6-423812
165423.4-433743
165434.8-433802
165219.0-441401
165111.6-440238
163750.8-465545
163520.5-472830
163248.5-474506
Name
CXO J
CSCg
J170440.6-411126
J170442.6-410920
J170117.9-421337
J170058.1-421036
J170019.2-422019
J163750.8-465544
J163520.5-472832
J163248.6-474505
Name
2XMMi
XMMi-DR3h
T HE C H I C AGO S URVEY
31
Source ID
ChI
(ID, Date,
Inst, Exp)
RA
(J2000)
0.6
0.6
0.4
0.3
0.7
0.3
0.6
0.6
0.5
0.3
0.3
0.4
0.4
0.3
0.6
0.3
0.6
0.7
0.5
0.9
0.3
1.3
0.3
0.4
0.6
1.1
0.7
1.0
0.4
0.4
0.3
0.9
0.6
1.56
1.56
2.84
1.16
2.25
2.94
0.49
0.26
0.22
1.97
2.75
0.62
1.52
0.68
1.43
1.41
2.02
2.16
0.22
2.78
0.37
0.28
0.48
2.29
1.84
2.37
0.42
0.77
0.70
2.73
2.97
−36:51:31.8
−36:51:24.4
−36:52:09.7
−37:01:55.2
−37:01:12.7
−37:00:10.6
−37:03:22.2
−37:10:37.4
−35:33:41.4
−35:32:31.3
−35:30:54.7
−35:16:22.9
−35:15:22.5
−35:04:18.4
−35:05:00.7
−35:04:56.7
−35:02:05.6
−35:02:09.5
−35:40:52.5
−35:41:48.1
−32:07:9.8
−31:41:23.4
−31:41:09.8
−31:39:30.1
−25:54:58.0
−25:53:54.4
−25:53:07.1
−20:05:11.5
−20:05:08.2
−20:04:22.2
−20:01:36.3
wav
(00 )
0.8
0.8
1.2
0.9
1.0
1.2
0.8
0.8
0.9
1.3
0.8
0.8
1.5
0.8
0.9
1.0
0.8
1.2
0.8
0.9
0.8
0.8
0.8
0.8
0.8
0.9
0.9
0.9
0.8
0.8
1.0
0.9
0.9
Total
(00 )
Positional Errorsd
2.87
2.32
from
ASCA (0 )
Offsetc
−37:16:14.3
−37:17:15.8
Dec
(J2000)
wavdetect Position
J171715-3718_1
17:17:07.59
J171715-3718_2
17:17:23.99
AX J171910-3652 8157 2007-10-26 ACIS-S 2.41ks
J171910-3652_1
17:19:06.24
J171910-3652_2
17:19:13.10
J171910-3652_3
17:19:24.07
AX J171922-3703 10525 2009-02-08 ACIS-S 7.65ks
J171922-3703_1
17:19:20.88
J171922-3703_2†
17:19:29.90
J171922-3703_3
17:19:27.08
J171922-3703_4
17:19:21.43
AX J172050-3710 10520 2009-06-19 ACIS-S 6.78ks
J172050-3710_1
17:20:51.80
AX J172550-3533 10514 2009-02-06 ACIS-S 5.38ks
J172550-3533_1
17:25:49.58
J172550-3533_2
17:25:58.53
J172550-3533_3
17:25:50.24
AX J172623-3516 8154 2007-10-26 ACIS-S 2.31ks
J172623-3516_1
17:26:25.52
J172623-3516_2
17:26:25.89
AX J172642-3504 10522 2009-02-06 ACIS-S 7.36ks
J172642-3504_1
17:26:39.21
J172642-3504_2
17:26:37.20
J172642-3504_3
17:26:47.45
J172642-3504_4†
17:26:45.22
J172642-3504_5†
17:26:36.84
AX J172642-3540 8222 2007-10-23 HRC-I 1.17ks
J172642-3540_1
17:26:41.73
J172642-3540_2* 17:26:55.49
AX J173548-3207 8148 2007-10-26 ACIS-S 2.01ks
J173548-3207_1
17:35:46.28
AX J173628-3141 8158 2007-10-26 ACIS-S 2.51ks
J173628-3141_1
17:36:27.31
J173628-3141_2
17:36:25.82
J173628-3141_3
17:36:35.48
AX J175331-2538 8149 2007-10-26 ACIS-S 2.01ks
J175331-2538
No Detection
AX J175404-2553 10521 2009-08-03 ACIS-S 6.76ks
J175404-2553_1†
17:54:01.73
J175404-2553_2* 17:54:14.42
J175404-2553_3
17:54:02.52
AX J180816-2021 8151 2007-10-26 ACIS-S 2.11ks
J180816-2021
No Detection
AX J180857-2004 10518 2009-02-10 ACIS-S 6.47ks
J180857-2004_1
18:08:59.25
J180857-2004_2
18:08:59.11
J180857-2004_3
18:09:08.97
J180857-2004_4
18:08:58.76
ChIcAGOb
Chandra Obsa
19+5
−4
0.0+1.9
−0.0
5.0+3.4
−2.2
95+11
−10
8.9+4.1
−2.9
9.0+4.1
−2.9
8.8+4.1
−2.9
0.0+1.9
−0.0
0.0+1.9
−0.0
280+18
−17
1.0+2.3
−0.9
35+7
−6
34+7
−6
35+7
−6
5.0+3.4
−2.2
7.9+4.0
−2.8
1.0+2.3
−0.9
1.9+2.7
−1.3
16+5
−4
0.0+1.9
−0.0
19+5
−4
11+4
−3
20+6
−4
114+12
−11
12+5
−3
143+13
−12
8.7+4.1
−2.9
+5
15−4
6.8+3.8
−2.6
314+19
−18
43+8
−7
44+8
−7
40+7
−6
43+8
−7
5.9+3.6
−2.4
87+10
−9
5.7+3.6
−2.3
4.6+3.4
−2.1
19+5
−4
3.9+3.2
−1.9
1.9 ± 0.2
2.3 ± 0.4
1.3 ± 0.2
1.7 ± 0.2
1.1 ± 0.6
1.7 ± 0.1
1.9 ± 0.3
2.2 ± 0.4
2.6 ± 0.4
1.6 ± 0.1
1.9 ± 0.2
1.4 ± 0.2
1.5 ± 0.2
1.5 ± 0.4
1.7 ± 0.8
1.5 ± 0.1
1.4 ± 0.3
0.7 ± 0.4
1.1 ± 0.5
1.0 ± 0.1
6.2 ± 0.4
2.9 ± 0.5
0.9 ± 0.0
1.1 ± 0.2
4.5 ± 0.2
0.9 ± 0.1
4.2 ± 0.3
3.9 ± 0.5
1.0 ± 0.0
4.7 ± 0.3
1.2 ± 0.1
1.3 ± 0.1
1.4 ± 0.1
1.2 ± 0.4
3.7 ± 0.2
2.5 ± 0.8
2.4 ± 0.9
1.0 ± 0.1
0.0+1.9
−0.0
11+4
−3
1.7 ± 0.2
1.7 ± 0.1
2.2 ± 0.3
1.1 ± 0.3
3.3 ± 0.3
3.2 ± 0.2
1.2 ± 0.1
1.2 ± 0.4
39+7
−6
63+9
−8
+1.9
0.0−0.0
3.9+3.2
−1.9
4.8+3.4
−2.1
15+5
−4
6.9+3.8
−2.6
9.0+4.1
−2.9
43+8
−7
77+10
−9
+3.8
6.7−2.5
13+5
−4
2.2 ± 0.2
4.9 ± 0.2
28+6
−5
0.0+1.9
−0.0
1.6 ± 0.4
3.8 ± 0.9
4.9+3.4
−2.1
0.9+2.3
−0.8
5.8+3.6
−2.3
2.6+2.9
−1.5
28+6
−5
1.7 ± 0.5
1.4 ± 0.5
0.9 ± 0.1
5.7 ± 1.4
0.0+1.9
−0.0
5.0+3.4
−2.2
3.9+3.2
−1.9
8.9+4.1
−2.9
0.0+1.9
−0.0
0.0+1.9
−0.0
10+4
−3
5.0+3.4
−2.2
3.9+3.2
−1.9
1.2 ± 0.2
1.4 ± 0.2
29+6
−5
16+5
−4
79+10
−9
4.7+3.4
−2.1
2.8+2.9
−1.6
1.0+2.3
−0.8
4.0+3.2
−1.9
8.0+4.0
−2.8
0.9+2.3
−0.8
42+8
−6
7.9+4.0
−2.8
+3.6
5.9−2.4
28+6
−5
134+13
−12
0.0+1.9
−0.0
+5
15−4
6.8+3.8
−2.6
15+5
−4
11+4
−3
+2.7
2.0−1.3
Quartile
Ratio
E50
(keV)
Energy Quantilesf
2-8 keV
45+8
−7
81+10
−9
2.7+2.9
−1.6
0.5-2
0.3-8
Net Countse
Table 1 — Continued
173546.2-320709
172641.7-354052
172625.5-351622
171906.2-365131
171913.1-365124
171924.0-365209
171707.6-371614
171723.9-371715
Name
CXO J
CSCg
J180909.0-200422
J172645.3-350205
J172639.2-350418
Name
2XMMi
XMMi-DR3h
32
Source ID
ChI
(ID, Date,
Inst, Exp)
RA
(J2000)
0.5
0.5
0.3
0.5
1.1
0.7
0.9
0.6
0.8
0.6
0.7
1.1
0.9
0.3
0.9
0.4
1.1
0.7
0.7
0.8
0.5
0.8
0.9
0.5
0.3
0.7
1.0
0.4
0.3
0.6
0.5
0.7
0.3
0.7
0.6
0.6
0.96
0.92
1.74
2.60
2.61
2.71
2.31
2.80
1.09
1.02
2.22
2.32
0.88
2.59
1.31
2.15
1.51
1.24
2.14
1.96
2.30
2.10
0.29
0.30
0.62
2.41
2.35
0.62
2.48
2.12
2.91
0.71
1.19
1.60
2.48
−18:28:19.9
−18:27:58.6
−18:27:47.0
−18:30:48.4
−18:28:21.7
−19:16:15.4
−18:44:03.0
−18:39:37.8
−18:43:27.6
−18:41:26.1
−18:40:34.8
−18:43:25.1
−18:42:08.8
−18:42:02.8
−18:41:46.3
−16:10:03.5
−16:06:27.4
−16:09:04.4
−16:08:23.5
−16:05:57.6
−16:10:11.8
−16:06:18.1
−15:59:40.2
−15:59:22.4
−15:59:16.3
−16:03:40.6
−16:03:12.5
−16:01:21.8
−15:49:27.3
−14:26:13.1
−14:22:32.6
−13:10:36.7
−13:12:07.7
−13:09:38.4
−13:08:50.2
wav
(00 )
0.8
1.0
0.9
0.9
0.9
1.0
0.9
1.2
0.8
0.8
0.9
0.8
1.0
1.3
1.0
1.0
1.1
0.9
1.1
1.2
0.9
1.1
0.9
1.0
1.4
1.2
0.8
1.2
0.8
1.2
0.9
0.8
0.9
1.3
1.0
0.8
Total
(00 )
Positional Errorsd
0.36
from
ASCA (0 )
Offsetc
−19:17:54.6
Dec
(J2000)
wavdetect Position
AX J181033-1917 9608 2008-05-11 ACIS-S 0.94ks
J181033-1917_1
18:10:32.80
AX J181116-1828 8162 2007-05-04 ACIS-S 2.78ks
J181116-1828_1
18:11:20.83
J181116-1828_2
18:11:13.11
J181116-1828_3
18:11:09.73
J181116-1828_4
18:11:19.08
J181116-1828_5
18:11:05.79
AX J181120-1913 8153 2007-10-26 ACIS-S 2.21ks
J181120-1913_1
18:11:23.27
AX J181213-1842 8167 2007-10-26 ACIS-S 3.0ks
J181213-1842_1†
18:12:20.87
J181213-1842_2
18:12:14.94
J181213-1842_3
18:12:12.54
J181213-1842_4
18:12:12.87
J181213-1842_5
18:12:08.65
J181213-1842_6
18:12:05.06
J181213-1842_7
18:12:10.38
J181213-1842_8
18:12:24.74
J181213-1842_9
18:12:09.14
AX J181705-1607 8160 2008-02-16 ACIS-S 2.63ks
J181705-1607_1
18:17:04.38
J181705-1607_2
18:17:03.79
J181705-1607_3
18:17:03.41
J181705-1607_4
18:16:56.60
J181705-1607_5†
18:17:05.84
J181705-1607_6
18:17:03.81
J181705-1607_7
18:16:59.70
AX J181852-1559 9609 2008-02-19 ACIS-S 1.63ks
J181852-1559_1
18:18:51.76
J181852-1559_2
18:18:51.38
J181852-1559_3
18:18:50.09
AX J181915-1601 10503 2009-08-06 ACIS-S 2.01ks
J181915-1601_1
18:19:12.98
J181915-1601_2†
18:19:22.19
J181915-1601_3
18:19:13.52
AX J181917-1548 9610 2008-09-25 HRC-I 1.15ks
J181917-1548_1
18:19:08.54
AX J182216-1425 10505 2009-03-12 ACIS-S 2.6ks
J182216-1425_1
18:22:24.24
J182216-1425_2
18:22:17.16
AX J182435-1311 11883 2010-06-19 ACIS-S 9.92ks
J182435-1311_1
18:24:37.61
J182435-1311_2
18:24:32.90
J182435-1311_3
18:24:33.72
J182435-1311_4
18:24:39.38
AX J182509-1253 10527 2009-02-15 ACIS-S 8.25ks
ChIcAGOb
Chandra Obsa
6.0+3.6
−2.4
2.0+2.7
−1.3
3.0+2.9
−1.7
0.0+1.9
−0.0
25+6
−5
27+6
−5
6.0+3.6
−2.4
41+7
−6
3.0+2.9
−1.7
3.0+2.9
−1.7
54+8
−7
75+10
−9
16+5
−4
8.9+4.1
−2.9
15+5
−4
0.7+2.3
−0.6
+3.6
5.9−2.4
3.9+3.2
−1.9
0.0+1.9
−0.0
0.0+1.9
−0.0
76+10
−9
3.9+3.2
−1.9
0.0+1.9
−0.0
4.7+3.4
−2.1
16+5
−4
8.9+4.1
−2.9
91+11
−10
4.5+3.4
−2.1
5.6+3.6
−2.3
8.5+4.1
−2.9
13+5
−4
3.0+2.9
−1.7
29+6
−5
48+8
−7
0.0+1.9
−0.0
39+7
−6
0.0+1.9
−0.0
3.0+2.9
−1.6
1.0+2.3
−0.9
2.9+2.9
−1.6
1.0+2.3
−0.8
10+4
−3
7.0+3.8
−2.6
0.9+2.3
−0.8
0.0+1.9
−0.0
4.0+3.2
−1.9
1.0+2.3
−0.8
3.0+2.9
−1.6
1.0+2.3
−0.9
0.0+1.9
−0.0
2.9+2.9
−1.6
3.0+2.9
−1.6
5.0+3.4
−2.2
3.8+3.2
−1.9
3.9+3.2
−1.9
11+4
−3
6.9+3.8
−2.6
3.8+3.2
−1.9
2.3 ± 0.3
2.0 ± 0.3
1.8 ± 0.1
0.9 ± 0.6
2.2 ± 0.3
1.6 ± 0.8
4.9 ± 0.2
4.3 ± 0.5
1.5 ± 0.1
1.2 ± 1.0
4.0 ± 0.4
1.7 ± 0.3
1.1 ± 0.1
1.1 ± 0.1
1.6 ± 0.3
1.6 ± 0.2
1.0 ± 0.1
3.8 ± 0.3
2.3 ± 0.3
2.4 ± 0.3
1.7 ± 0.3
1.7 ± 0.4
3.3 ± 0.6
4.6 ± 0.8
1.6 ± 0.4
1.3 ± 0.1
2.5 ± 0.5
1.2 ± 0.3
0.0+1.9
−0.0
0.0+1.9
−0.0
3.0+2.9
−1.6
2.0+2.7
−1.3
1.0+2.3
−0.9
0.0+1.9
−0.0
96+11
−10
0.0+1.9
−0.0
4.0+3.2
−1.9
9.0+4.1
−3.0
7.0+3.8
−2.6
2.0+2.7
−1.3
1.9+2.7
−1.3
2.0+2.7
−1.3
4.9+3.4
−2.2
17+5
−4
5.0+3.4
−2.2
18+5
−4
9.0+4.1
−3.0
6.8+3.8
−2.6
4.9+3.4
−2.2
3.9+3.2
−1.9
3.0+2.9
−1.7
4.7+3.4
−2.1
113+12
−11
4.9+3.4
−2.1
+6
22−5
1.1 ± 0.2
3.8 ± 0.2
1.3 ± 0.1
1.0 ± 0.2
6.0+3.6
−2.4
0.0+1.9
−0.0
5.9+3.6
−2.4
2.4 ± 0.6
1.5 ± 0.3
1.6 ± 0.3
1.9 ± 0.5
3.4 ± 0.6
1.0 ± 0.2
0.9 ± 0.2
2.3 ± 0.5
1.1 ± 0.6
1.3 ± 0.2
2.3 ± 0.7
6.9+3.8
−2.6
50+8
−7
10+4
−3
+3.2
3.8−1.9
7.9+4.0
−2.8
1.3 ± 0.3
2.8 ± 0.3
1.1 ± 0.1
8.0+4.0
−2.8
9.0+4.1
−3.0
0.0+1.9
−0.0
35+7
−6
1.0+2.3
−0.9
+1.9
0.0−0.0
7.0+3.8
−2.6
Quartile
Ratio
7.0+3.8
−2.6
15+5
−4
9.0+4.1
−3.0
+3.2
3.9−1.9
0.9+2.3
−0.8
E50
(keV)
1.6 ± 0.5
2-8 keV
1.3 ± 0.3
0.5-2
Energy Quantilesf
1.0+2.3
−0.9
0.3-8
Net Countse
Table 1 — Continued
181907.8-154928
181922.1-160309
181851.8-155940
181851.3-155922
J181922.1-160310
J181703.8-161012
J181209.2-184149
181209.1-184146
181705.8-160557
J181210.5-184208
J181113.2-182800
Name
2XMMi
XMMi-DR3h
181210.3-184208
181113.1-182758
181109.7-182746
181032.7-191755
Name
CXO J
CSCg
T HE C H I C AGO S URVEY
33
Source ID
ChI
(ID, Date,
Inst, Exp)
RA
(J2000)
0.3
0.5
0.4
0.8
0.3
0.4
0.5
0.9
0.7
0.4
0.5
0.3
0.7
0.6
0.3
0.4
1.0
0.5
0.3
0.4
0.4
0.7
0.9
0.9
0.6
0.5
0.6
0.8
0.7
0.3
0.7
0.3
1.09
1.50
1.21
1.58
2.07
2.94
1.24
0.59
0.84
0.60
1.29
0.84
1.34
2.83
1.56
0.85
1.26
1.24
2.60
3.03
2.91
1.54
0.96
1.25
2.81
1.47
1.61
0.98
0.50
−11:45:28.7
−11:45:24.7
−12:14:50.8
−12:05:14.1
−12:04:42.2
−12:08:43.4
−12:07:05.7
−12:06:32.2
−10:09:24.8
−10:09:10.6
−10:08:00.1
−09:39:05.7
−08:28:30.8
−08:25:18.9
−08:23:03.3
−08:22:26.8
−08:21:40.2
−08:22:22.6
−08:21:01.6
−08:20:48.4
−08:21:03.2
−07:54:38.2
−05:44:15.5
−05:44:03.4
−03:58:18.6
−03:05:51.2
−02:41:20.1
−02:39:53.4
−01:56:33.3
wav
(00 )
0.8
0.8
1.0
1.0
1.1
0.8
0.9
0.9
0.8
0.8
0.8
0.8
1.0
1.1
1.1
0.8
1.2
0.8
0.8
1.0
0.9
0.9
1.2
1.0
0.8
0.8
0.8
1.1
0.8
0.8
0.9
0.8
Total
(00 )
Positional Errorsd
0.33
2.00
1.45
from
ASCA (0 )
Offsetc
−12:53:31.6
−12:52:11.1
−12:51:57.6
Dec
(J2000)
wavdetect Position
J182509-1253_1
18:25:08.73
J182509-1253_2
18:25:03.16
J182509-1253_3
18:25:11.59
AX J182530-1144 10515 2009-02-19 ACIS-S 5.88ks
J182530-1144_1* 18:25:26.77
J182530-1144_2
18:25:24.77
AX J182538-1214 10504 2009-03-09 ACIS-S 2.27ks
J182538-1214_1
18:25:33.69
AX J182651-1206 10516 2009-02-15 ACIS-S 5.68ks
J182651-1206_1
18:26:55.40
J182651-1206_2†
18:26:55.83
J182651-1206_3
18:26:58.59
J182651-1206_4
18:26:46.88
J182651-1206_5
18:26:48.75
AX J183116-1008 10506 2009-02-13 ACIS-S 2.82ks
J183116-1008_1
18:31:16.52
J183116-1008_2* 18:31:16.44
J183116-1008_3
18:31:21.00
AX J183206-0938 9611 2008-05-31 ACIS-S 1.04ks
J183206-0938_1
18:32:08.95
AX J183345-0828 10524 2009-02-13 ACIS-S 8.03ks
J183345-0828_1
18:33:40.39
J183345-0828_2
18:33:45.30
AX J183356-0822 11884 2010-07-06 ACIS-S 9.92ks
J183356-0822_1†
18:33:50.37
J183356-0822_2
18:33:59.51
J183356-0822_3
18:33:55.97
J183356-0822_4
18:33:52.12
J183356-0822_5
18:33:49.44
J183356-0822_6
18:34:05.42
J183356-0822_7
18:34:05.65
AX J183518-0754 8166 2008-02-16 HRC-I 3.15ks
J183518-0754_1
18:35:24.44
AX J183607-0756 8159 2008-02-16 ACIS-S 2.52ks
J183607-0756
No Detection
AX J184008-0543 8144 2008-02-19 ACIS-S 1.63ks
J184008-0543_1
18:40:04.88
J184008-0543_2
18:40:03.45
AX J184400-0355 8169 2008-02-29 ACIS-S 3.12ks
J184400-0355_1
18:44:03.29
AX J184447-0305 8163 2007-05-24 ACIS-S 2.72ks
J184447-0305_1
18:44:41.84
AX J184652-0240 8146 2008-02-29 ACIS-S 1.91ks
J184652-0240_1
18:46:47.68
J184652-0240_2
18:46:56.27
AX J184738-0156 9612 2008-05-27 ACIS-S 1.63ks
J184738-0156_1
18:47:36.65
AX J184741-0219 10512 2009-02-21 ACIS-S 5.69ks
ChIcAGOb
Chandra Obsa
39+7
−6
1.0+2.3
−0.8
117+12
−11
47+8
−7
3.0+2.9
−1.6
3.0+2.9
−1.7
86+10
−9
3.9+3.2
−1.9
120+12
−11
3.0+2.9
−1.6
1.0+2.3
−0.8
3.9+3.2
−1.9
1.5 ± 0.2
2.0 ± 0.1
1.9 ± 0.1
4.2 ± 0.2
1.7 ± 0.6
1.0 ± 0.2
0.0+1.9
−0.0
11+4
−3
11+4
−3
2.3 ± 0.3
1.9 ± 0.3
3.8 ± 0.3
4.6 ± 0.8
8.9+4.1
−2.9
6.0+3.6
−2.4
0.0+1.9
−0.0
0.0+1.9
−0.0
8.9+4.1
−2.9
6.0+3.6
−2.4
9.1+4.3
−3.0
1.6 ± 0.4
2.1 ± 0.1
1.3 ± 0.3
1.6 ± 0.3
2.2 ± 0.4
1.8 ± 0.5
1.5 ± 0.6
1.4 ± 0.2
4.5 ± 0.3
3.1 ± 0.4
3.4 ± 0.6
5.0 ± 0.5
4.1 ± 0.9
1.6 ± 0.5
1.8+2.7
−1.2
66+9
−8
16+5
−4
12+5
−3
7.8+4.0
−2.7
+3.6
5.9−2.4
1.8+2.7
−1.2
7.9+4.0
−2.8
0.0+1.9
−0.0
6.0+3.6
−2.4
0.9+2.3
−0.8
0.0+1.9
−0.0
0.0+1.9
−0.0
5.0+3.4
−2.2
10+4
−3
66+9
−8
22+6
−5
13+5
−4
7.8+4.0
−2.7
+3.6
5.7−2.3
6.6+3.8
−2.5
1.4 ± 0.2
2.6 ± 0.3
29+6
−5
0.0+1.9
−0.0
11+4
−3
4.0+3.2
−1.9
40+7
−6
3.8+3.2
−1.9
1.3 ± 0.1
3.3 ± 0.2
121+12
−11
32+7
−6
153+13
−12
1.1 ± 0.7
1.8 ± 0.9
2.0+2.7
−1.3
2.9+2.9
−1.6
1.7 ± 0.1
3.4 ± 0.2
80+10
−9
5.9+3.6
−2.4
2.3 ± 0.1
1.2 ± 0.3
1.1 ± 0.4
5.1 ± 0.4
1.6 ± 0.2
3.8 ± 1.5
86+10
−9
2.8+2.9
−1.6
5.9+3.6
−2.4
1.6 ± 0.5
2.6 ± 0.6
5.0+3.4
−2.2
0.0+1.9
−0.0
14+5
−4
5.9+3.6
−2.4
+4.0
7.9−2.8
2.9+2.9
−1.6
0.0+1.9
−0.0
0.0+1.9
−0.0
15+5
−4
2.0+2.7
−1.3
7.9+4.0
−2.8
3.0+2.9
−1.6
13+5
−4
22+6
−5
10+4
−3
1.6 ± 0.4
5.0+3.4
−2.2
26+6
−5
32+7
−6
1.0 ± 0.1
182+15
−13
54+8
−7
2.8+2.9
−1.6
236+16
−15
1.5 ± 0.1
1.6 ± 0.5
1.8 ± 0.2
1.2 ± 0.1
0.9 ± 0.2
4.4 ± 0.2
1.2 ± 0.1
11+4
−3
0.0+1.9
−0.0
46+8
−7
78+10
−9
10+4
−3
0.9+2.3
−0.8
90+11
−9
10+4
−3
47+8
−7
Quartile
Ratio
E50
(keV)
Energy Quantilesf
3.5 ± 0.2
2-8 keV
0.5-2
0.3-8
Net Countse
Table 1 — Continued
184736.6-015633
184647.6-024120
184403.2-035819
184004.8-054415
184003.4-054403
183208.9-093905
183116.4-100924
Name
CXO J
CSCg
J184736.6-015633
J184441.9-030551
J183350.4-082300
J183359.6-082225
J183356.1-082138
J183345.1-082520
J183116.5-100926
J182533.6-121452
Name
2XMMi
XMMi-DR3h
34
Source ID
ChI
(ID, Date,
Inst, Exp)
RA
(J2000)
Dec
(J2000)
wavdetect Position
J184741-0219_1* 18:47:48.01 −02:21:25.4
J184741-0219_2
18:47:36.52 −02:19:32.2
J184741-0219_3
18:47:37.28 −02:18:49.4
J184741-0219_4
18:47:42.99 −02:18:22.2
J184741-0219_5
18:47:44.30 −02:19:16.5
AX J185608+0218 9613 2008-03-01 ACIS-S 1.41ks
J185608+0218_1
18:56:09.55 +02:17:44.0
J185608+0218_2
18:56:05.53 +02:18:22.1
AX J185643+0220 10513 2009-02-22 ACIS-S 5.65ks
J185643+0220_1
18:56:48.00 +02:18:36.6
J185643+0220_2
18:56:43.61 +02:19:21.5
J185643+0220_3
18:56:43.98 +02:20:35.9
AX J185750+0240 8150 2007-07-25 ACIS-S 2.21ks
J185750+0240_1
18:57:53.65 +02:40:10.8
AX J185905+0333 8143 2007-07-20 ACIS-S 1.76ks
J185905+0333
No Detection
AX J190534+0659 8147 2007-07-12 ACIS-S 2.15ks
J190534+0659_1
19:05:32.78 +06:59:33.6
AX J190749+0803 8168 2007-07-22 ACIS-S 3.21ks
J190749+0803_1
19:07:48.84 +08:03:42.9
AX J190814+0832 8223 2007-06-26 ACIS-S 3.48ks
J190814+0832_1
19:08:11.18 +08:29:53.1
J190814+0832_2
19:08:09.95 +08:31:47.7
J190814+0832_3
19:08:15.90 +08:32:40.6
J190814+0832_4
19:08:19.00 +08:33:43.8
AX J190818+0745 9614 2008-02-28 ACIS-S 1.43ks
J190818+0745_1
19:08:13.20 +07:43:57.7
J190818+0745_2
19:08:25.46 +07:44:28.3
J190818+0745_3
19:08:22.73 +07:47:48.9
AX J191046+0917 9615 2008-05-31 ACIS-S 1.63ks
J191046+0917
No Detection
AX J194152+2251 8164 2007-07-16 ACIS-S 2.71ks
J194152+2251_1* 19:41:56.53 +22:49:06.9
J194152+2251_2
19:41:54.60 +22:51:12.5
J194152+2251_3
19:41:52.95 +22:54:18.3
AX J194310+2318 10502 2009-02-26 ACIS-S 2.05ks
J194310+2318_1
19:43:06.77 +23:16:12.5
J194310+2318_2* 19:43:07.78 +23:17:03.1
J194310+2318_3
19:43:04.94 +23:18:33.8
J194310+2318_4† 19:43:11.33 +23:20:38.9
J194310+2318_5
19:43:10.98 +23:17:45.5
J194310+2318_6
19:43:07.07 +23:18:31.7
J194310+2318_7† 19:43:14.53 +23:20:16.4
J194310+2318_8
19:43:13.06 +23:17:25.2
J194310+2318_9
19:43:12.58 +23:18:15.8
J194310+2318_10 19:43:08.44 +23:18:17.3
AX J194332+2323 10517 2009-02-15 ACIS-S 5.88ks
ChIcAGOb
Chandra Obsa
1.5
0.6
0.4
0.5
0.8
0.3
0.5
0.6
0.3
0.6
0.3
0.4
0.3
1.0
0.4
0.6
0.8
0.3
0.5
1.1
1.3
0.3
1.1
0.6
0.8
0.8
0.7
0.4
0.4
0.6
0.7
0.6
0.6
0.61
0.62
2.06
0.93
0.37
0.71
0.72
0.27
2.70
1.29
0.43
1.71
2.00
1.92
2.59
2.73
0.63
2.59
2.76
1.88
1.27
1.82
1.09
0.81
1.73
1.55
0.78
0.70
wav
(00 )
0.9
1.1
1.1
1.0
0.8
0.8
0.9
1.0
0.9
0.9
1.5
0.8
1.3
0.8
0.9
1.3
1.2
0.8
0.9
1.1
0.8
0.8
0.8
0.9
0.8
0.9
0.8
0.8
1.7
0.9
0.8
0.9
1.0
Total
(00 )
Positional Errorsd
2.93
1.30
1.02
0.78
0.80
from
ASCA (0 )
Offsetc
18+5
−4
9.0+4.1
−3.0
1.0+2.3
−0.8
31+7
−6
5.0+3.4
−2.2
0.0+1.9
−0.0
79+10
−9
4.0+3.2
−1.9
1.0+2.3
−0.9
13+5
−4
3.0+2.9
−1.7
22+6
−5
91+11
−10
3.8+3.2
−1.9
43+8
−7
4.9+3.4
−2.2
3.8+3.2
−1.9
138+13
−12
12+5
−3
+2.9
3.0−1.6
2.9+2.9
−1.6
72+10
−8
2.9+2.9
−1.6
1.0 ± 0.1
0.8 ± 0.3
1.8 ± 0.1
3.7 ± 1.3
59+9
−8
0.0+1.9
−0.0
58+9
−8
7.9+4.0
−2.8
+1.9
0.0−0.0
0.9 ± 0.5
1.0 ± 0.1
1.6 ± 0.1
1.2 ± 0.4
2.7 ± 1.5
1.1 ± 0.1
1.0 ± 0.4
1.3 ± 0.2
1.8 ± 0.4
2.0 ± 1.0
0.6 ± 0.4
2.1 ± 0.3
1.4 ± 0.4
1.4 ± 0.2
1.9 ± 0.3
1.6 ± 0.1
0.9 ± 0.1
2.9+2.9
−1.6
12+5
−3
0.0+1.9
−0.0
3.9+3.2
−1.9
1.1 ± 0.2
1.7 ± 0.1
3.7 ± 0.2
82+10
−9
1.2 ± 0.1
1.3 ± 0.4
1.6 ± 0.2
4.0+3.2
−1.9
3.4 ± 0.3
1.1 ± 0.2
3.2 ± 0.4
33+7
−6
2.0+2.7
−1.3
0.9+2.3
−0.8
0.0+1.9
−0.0
3.0+2.9
−1.6
1.0+2.3
−0.8
3.0+2.9
−1.6
0.0+1.9
−0.0
2.0+2.7
−1.3
11+4
−3
44+8
−7
1.4 ± 0.5
1.4 ± 0.2
1.9 ± 0.3
1.3 ± 0.2
3.9 ± 0.2
2.9 ± 0.5
1.9+2.7
−1.3
65+9
−8
3.9+3.2
−1.9
2.0+2.7
−1.3
4.0+3.2
−1.9
30+7
−5
17+5
−4
+3.6
6.0−2.4
2.0+2.7
−1.3
6.0+3.6
−2.4
2.0+2.7
−1.3
9.0+4.1
−2.9
4.0+3.2
−1.9
0.9+2.3
−0.8
11+4
−3
69+9
−8
+3.4
4.8−2.1
1.6 ± 0.1
1.8 ± 0.4
1.0 ± 0.0
4.9 ± 0.9
20+6
−4
7.0+3.8
−2.6
4.0+3.2
−1.9
165+14
−13
1.0+2.3
−0.9
192+15
−14
8.0+4.0
−2.8
Quartile
Ratio
1.3 ± 0.7
1.9 ± 0.2
1.3 ± 0.3
E50
(keV)
Energy Quantilesf
1.7 ± 0.5
5.0 ± 0.3
1.3 ± 0.3
0.9+2.3
−0.8
31+7
−6
1.9+2.7
−1.3
0.0+1.9
−0.0
2-8 keV
15+5
−4
4.9+3.4
−2.2
1.0+2.3
−0.8
6.9+3.8
−2.6
4.0+3.2
−1.9
2.6+2.9
−1.5
5.8+3.6
−2.4
32+7
−6
8.8+4.1
−2.9
4.0+3.2
−1.9
19+5
−4
3.7+3.2
−1.8
+3.2
4.0−1.9
4.9+3.4
−2.1
31+7
−6
20+6
−4
+3.8
7.0−2.6
4.9+3.4
−2.2
5.8+3.6
−2.4
4.0+3.2
−1.9
0.5-2
0.3-8
Net Countse
Table 1 — Continued
194154.6+225112
190813.2+074357
190825.4+074428
190809.9+083147
190748.8+080342
190532.7+065933
185753.6+024010
185609.5+021743
Name
CXO J
CSCg
Name
2XMMi
XMMi-DR3h
T HE C H I C AGO S URVEY
35
a
RA
(J2000)
Dec
(J2000)
0.8
1.1
1.0
0.3
0.9
0.7
0.4
0.6
0.5
0.5
1.17
2.75
2.37
0.33
1.63
2.40
0.37
0.89
0.28
1.74
1.0
0.8
0.9
0.8
0.9
1.1
0.8
1.1
1.3
1.2
0.8
0.9
1.0
1.0
0.9
1.2
1.1
1.1
Total
(00 )
6.9+3.8
−2.6
28+6
−5
5.7+3.6
−2.3
6.8+3.8
−2.6
12+5
−3
7.0+3.8
−2.6
25+6
−5
3.0+2.9
−1.7
7.0+3.8
−2.6
12+5
−3
0.0+1.9
−0.0
2.7+2.9
−1.6
2.7+2.9
−1.6
0.0+1.9
−0.0
0.0+1.9
−0.0
97+11
−10
17+5
−4
114+12
−11
2.7+2.9
−1.6
2.0+2.7
−1.3
0.0+1.9
−0.0
1.0+2.3
−0.8
1.0 ± 0.1
1.1 ± 0.1
1.4 ± 0.5
1.5 ± 0.2
1.1 ± 0.1
3.8 ± 0.1
2.1 ± 0.6
1.5 ± 0.4
1.4 ± 0.5
1.9 ± 0.4
2.0 ± 0.4
1.6 ± 0.1
1.6 ± 1.1
1.3 ± 1.0
1.6 ± 0.5
1.5 ± 0.1
1.1 ± 0.6
0.8 ± 0.1
1.0+2.3
−0.9
4.0+3.2
−1.9
2.0+2.7
−1.3
2.1 ± 0.3
1.5 ± 0.2
3.0+2.9
−1.7
4.0+3.2
−1.9
3.0+2.9
−1.6
1.4 ± 0.4
1.3 ± 0.2
3.0+2.9
−1.6
0.0+1.9
−0.0
0.0+1.9
−0.0
0.9+2.3
−0.8
1.0+2.3
−0.9
0.9+2.3
−0.8
0.0+1.9
−0.0
0.0+1.9
−0.0
12+5
−3
4.0+3.2
−1.9
6.9+3.8
−2.6
3.0+2.9
−1.7
13+5
−4
5.9+3.6
−2.4
8.0+4.0
−2.8
4.9+3.4
−2.2
15+5
−4
3.9+3.2
−1.9
6.8+3.8
−2.6
3.9+3.2
−1.9
14+5
−4
6.8+3.8
−2.6
8.7+4.1
−2.9
4.8+3.4
−2.1
Quartile
Ratio
E50
(keV)
Energy Quantilesf
2-8 keV
0.5-2
0.3-8
Net Countse
194938.3+263149
Name
CXO J
CSCg
Name
2XMMi
XMMi-DR3h
The ChIcAGO source position error information. wav: The 95% position error circle of the ChIcAGO source wavdetect position. This was calculated using Equation 5 of Hong et al. (2005). Total: The total 95% position error circle of
The offset, in arcminutes, between the ChIcAGO source and the original AGPS source position published by Sugizaki et al. (2001).
The ChIcAGO source name. Those ChIcAGO sources marked with a * have a probability of false detection that is > 10−5 . The ChIcAGO sources marked with a † fall in the chip gap between ACIS-S CCDs 6 and 7.
Details of the Chandra observation: the observation identification number (ID), the date of the observation (yyyy-mm-dd), the Chandra instrument used for the observation, and the exposure time of the observation in ks.
0.4
0.6
0.8
0.7
0.5
1.0
0.8
0.9
wav
(00 )
Positional Errorsd
1.30
1.06
2.67
1.44
2.53
2.61
2.85
2.20
from
ASCA (0 )
Offsetc
photon detected) used in quantile analysis: 3×(E25 − 0.3)/(E75 − 0.3). See Section 2.3.1 for further details.
g
The corresponding Chandra Source Catalog name for each ChIcAGO source (Evans et al. 2010).
h
The corresponding 2XMMi DR3 name for each ChIcAGO source (Watson et al. 2009).
counts have been background subtracted and the upper and lower 1σ confidence limits were calculated using Gehrels (1986) statistics.
f
The values used in the quantile analysis (results in Tables 3 and 4). E50 is the 50% photon detected in the 0.3 − 8.0 keV energy band. The quartile ratio is the ratio of the E25 (energy of the 25% photon detected) and E75 (energy of the 75%
the ChIcAGO source taking into account the wavdetect position error and the absolute astrometric accuracy of Chandra. Both errors are in arcseconds.
e
The net number of counts in the 0.3 − 8.0, 0.5 − 2.0 and 2.0 − 8.0 keV energy ranges detected from each ChIcAGO source. The source counts were calculated using a source region with a radius equal to 95% of the PSF at 1.5 keV. The total
d
c
b
Source ID
ChI
(ID, Date,
Inst, Exp)
wavdetect Position
J194332+2323_1
19:43:27.18 +23:23:31.2
J194332+2323_2
19:43:31.97 +23:24:55.6
J194332+2323_3
19:43:43.32 +23:24:56.4
J194332+2323_4
19:43:29.79 +23:25:09.7
J194332+2323_5† 19:43:33.02 +23:26:24.6
J194332+2323_6
19:43:23.05 +23:25:17.5
J194332+2323_7
19:43:28.11 +23:21:13.6
J194332+2323_8
19:43:23.24 +23:23:26.4
AX J194622+2436 8232 2007-03-12 ACIS-S 1.34ks
J194622+2436_1
19:46:24.99 +24:35:46.8
J194622+2436_2
19:46:34.33 +24:37:05.9
J194622+2436_3
19:46:15.28 +24:38:32.1
AX J194939+2631 8236 2008-01-05 ACIS-S 1.72ks
J194939+2631_1
19:49:38.38 +26:31:49.0
AX J194951+2534 8139 2008-02-08 HRC-I 1.15ks
J194951+2534_1* 19:49:48.84 +25:35:53.1
AX J195006+2628 10511 2009-01-02 ACIS-S 5.35ks
J195006+2628_1
19:50:16.16 +26:27:17.1
J195006+2628_2
19:50:04.86 +26:28:21.8
J195006+2628_3
19:50:03.54 +26:27:43.3
J195006+2628_4
19:50:05.25 +26:28:17.5
J195006+2628_5
19:50:01.10 +26:29:34.2
ChIcAGOb
Chandra Obsa
Table 1 — Continued
36
15411580-5521286
15455824-5444247
P**
M
M
7.38 ± 0.05
8.96 ± 0.02
> 19.2 ± 0.2
7.95 ± 0.02
9.51 ± 0.03
P
> 21.4 ± 0.0
18243761-1310369
18250874-1253318
M
M
18.5 ± 0.2
11.73 ± 0.02
> 20.3 ± 0.3
9.09 ± 0.03
18192219-1603123
9.69 ± 0.06
> 15.4 ± 0.0
17.1 ± 0.2
11.48 ± 0.03
> 18.8 ± 0.3
8.3 ± 0.06
11.63 ± 0.04
18085910-2005084
M
P*
P*
M
P
M
8.83 ± 0.04
> 13.44 ± 0.0
17264172-3540523
17354627-3207099
M
M
9.33 ± 0.02
14.19 ± 0.04
17255853-3532315
17255031-3530553
17262553-3516229
9.55 ± 0.02
20.87 ± 0.32
13.71 ± 0.04
9.64 ± 0.02
8.70 ± 0.04
9.90 ± 0.02
> 21.6 ± 0.2
14.26 ± 0.04
10.02 ± 0.03
9.46 ± 0.02
17205180-3710371
9.65 ± 0.03
10.26 ± 0.03
18120913-1841459
16570375-4254413
M
P**
M
M
M
9.27 ± 0.03
9.57 ± 0.03
16.38 ± 0.11
15.9 ± 0.2
9.52 ± 0.03
19.01 ± 0.11
10.35 ± 0.03
21.5 ± 0.5
11.02 ± 0.03
11.78 ± 0.03
17053981-4038123
17191309-3651241
15.6 ± 0.11
15.4 ± 0.2
8.86 ± 0.03
18.27 ± 0.11
9.67 ± 0.02
17.2 ± 0.2
10.25 ± 0.02
11.19 ± 0.02
9.02 ± 0.03
13.36 ± 0.04
14.69 ± 0.03
16204880-4942141
16324851-4745062
16375079-4655452
M
M
13.12 ± 0.02
9.71 ± 0.02
10.13 ± 0.05
10.19 ± 0.03
14.74 ± 0.11
17.01 ± 0.14
8.05 ± 0.03
13.4 ± 0.1
14.57 ± 0.06
13.82 ± 0.02
9.90 ± 0.02
11.02 ± 0.03
10.82 ± 0.02
15.20 ± 0.06
15461218-5443106
15502123-5409540
15503759-5407217
15533602-5348270
15582833-5335205
17005828-4210369
17044059-4111271
> 19.5 ± 0.15
8.93 ± 0.06
> 12.82 ± 0.0
> 21.9 ± 0.3
9.60 ± 0.02
> 13.52 ± 0.0
16564984-4238479
16.3 ± 0.1
7.88 ± 0.02
10.95 ± 0.03
8.10 ± 0.03
7.60 ± 0.04
17.1 ± 0.1
8.28 ± 0.02
14.12 ± 0.04
9.23 ± 0.04
8.93 ± 0.02
P
P
M
P
M
P
M
M
M
M
M
M
M,P,P
P
M
M,P,M
M,M,P
14403847-6001368
14452143-5949251
14454369-5932050
14465358-5919382
P
M
M
M
M
J143148-6021_3
J144042-6001_1
J144519-5949_2
J144547-5931_1
J144701-5919_1
J150436-5824_1
J153818-5541_1
J154122-5522_1
J154557-5443_1
J154557-5443_2
J154557-5443_3
J155035-5408_1
J155035-5408_3
J155331-5347_1
J155831-5334_1
J162011-5002_1
J162046-4942_1
J163252-4746_2
J163751-4656_1
J165105-4403_1
J165217-4414_1
J165420-4337_1
J165646-4239_1
J165646-4239_2
J165707-4255_1
J170017-4220_1
J170052-4210_1
J170444-4109_1
J170444-4109_2
J170536-4038_1
J171910-3652_2
J171922-3703_1
J172050-3710_1
J172550-3533_1
J172550-3533_2
J172550-3533_3
J172623-3516_1
J172642-3504_1
J172642-3540_1
J173548-3207_1
J175404-2553_3
J180857-2004_1
J180857-2004_2
J181116-1828_2
J181213-1842_7
J181213-1842_9
J181852-1559_2
J181915-1601_2
J181915-1601_3
J182435-1311_1
J182509-1253_1
J182509-1253_3
J182530-1144_2
H
K
7.06 ± 0.02
8.81 ± 0.02
8.61 ± 0.04
> 15.1 ± 0.0
16.1 ± 0.2
11.40 ± 0.02
> 18.0 ± 0.3
7.76 ± 0.02
8.74 ± 0.03
> 12.71 ± 0.0
9.44 ± 0.02
19.0 ± 0.24
13.59 ± 0.05
9.56 ± 0.02
8.32 ± 0.03
9.11 ± 0.03
9.42 ± 0.03
15.34 ± 0.11
15.2 ± 0.2
8.61 ± 0.03
18.23 ± 0.11
9.46 ± 0.02
14.7 ± 0.2
10.00 ± 0.02
10.91 ± 0.03
7.64 ± 0.03
> 9.27 ± 0.0
14.07 ± 0.11
12.93 ± 0.04
9.59 ± 0.02
9.82 ± 0.06
9.98 ± 0.03
14.58 ± 0.11
18.0 ± 0.5
8.68 ± 0.02
12.92 ± 0.05
15.6 ± 0.1
7.70 ± 0.02
9.30 ± 0.03
7.52 ± 0.02
6.82 ± 0.02
Near-Infrared Magnitudes
J
2MASS J
Data
ChI
2MASS name
NIRa
ChIcAGO Source
2009-04-12
2008-05-13
2008-05-13
2008-05-12
2009-04-14
2008-05-12
2007-07-29
2008-05-12
2008-05-13
2008-05-12
2007-06-25
2009-04-14
2009-04-14
2009-04-13
2005-05-12
yyyy-mm-dd
PANIC date
018.1759-00.1606
018.4867-00.1392
015.0392-00.3903
011.8954-00.1354
010.3179-00.1519
011.9905+00.1688
352.1660-00.2698
356.1769+00.1101
352.1998-00.0707
352.2063-00.0327
352.4741+00.0035
350.2693-00.1451
345.7335+00.2171
350.3441+00.3074
342.9535+00.0859
343.7749-00.0290
343.9762-00.0242
345.1795+00.0300
342.0899+00.0150
343.1338+00.2844
333.7304+00.2208
336.5085+00.1571
337.6914+00.0830
326.4461-00.0314
327.2633+00.0289
327.3210+00.0369
327.8592+00.0053
6.89 ± 0.04
8.75 ± 0.04
7.22 ± 0.05
11.35 ± 0.15
8.03 ± 0.14
13.71 ± 0.12
6.61 ± 0.05
8.75 ± 0.06
6.84 ± 0.04
11.27 ± 0.12
7.70 ± 0.20
13.56 ± 0.18
8.73 ± 0.04
13.33 ± 0.10
9.44 ± 0.04
8.21 ± 0.04
9.44 ± 0.04
8.12 ± 0.03
8.63 ± 0.03
13.23 ± 0.11
12.84 ± 0.15†
9.39 ± 0.04
9.05 ± 0.05
9.32 ± 0.05
9.38 ± 0.05
11.97 ± 0.09
9.87 ± 0.04
10.49 ± 0.06
13.32 ± 0.16†
8.38 ± 0.08
13.10 ± 0.08†
9.40 ± 0.03
9.01 ± 0.05
9.33 ± 0.04
9.39 ± 0.03
12.60 ± 0.06
9.88 ± 0.04
10.54 ± 0.06
14.05 ± 0.13†
8.40 ± 0.08
7.61 ± 0.05
7.43 ± 0.06
14.03 ± 0.15†
12.67 ± 0.17†
9.59 ± 0.05
9.65 ± 0.06
9.95 ± 0.06
12.54 ± 0.08†
9.60 ± 0.04
9.50 ± 0.05
9.97 ± 0.06
7.47 ± 0.05
8.18 ± 0.06
14.31 ± 0.07†
8.68 ± 0.06
12.91 ± 0.12
8.61 ± 0.05
12.78 ± 0.07
6.89 ± 0.04
6.33 ± 0.09†
7.07 ± 0.05
6.70 ± 0.09†
316.9656+00.1864
317.1882+00.3106
325.4962-00.1082
326.4069-00.0270
7.63 ± 0.05
M4.5
7.65 ± 0.06
M3.6
6.60 ± 0.03
8.65 ± 0.03
6.66 ± 0.03
7.43 ± 0.10
8.59 ± 0.03
9.47 ± 0.04
8.11 ± 0.03
11.59 ± 0.14†
9.37 ± 0.04
8.97 ± 0.05
9.30 ± 0.03
9.19 ± 0.04
11.51 ± 0.10
9.813 ± 0.06
10.56 ± 0.06
8.35 ± 0.05
7.45 ± 0.03
7.27 ± 0.03
11.75 ± 0.22†
9.51 ± 0.05
9.42 ± 0.06
9.80 ± 0.08
8.51 ± 0.04
6.708 ± 0.03
5.574 ± 0.03
7.64 ± 0.03
M5.8
GLIMPSE Magnitudesb
316.1785+00.0060
SSTGLMC G
GLIMPSE name
Table 2
ChIcAGO sources with > 20 X-ray counts and their infrared properties
6.47 ± 0.03
8.60 ± 0.04
6.25 ± 0.03
8.56 ± 0.02
9.47 ± 0.04
8.08 ± 0.02
9.33 ± 0.02
8.93 ± 0.03
9.25 ± 0.03
9.35 ± 0.04
11.77 ± 0.17
9.75 ± 0.04
10.58 ± 0.06
8.30 ± 0.04
7.39 ± 0.05
6.76 ± 0.03
9.58 ± 0.05
9.45 ± 0.05
9.72 ± 0.05
8.47 ± 0.03
11.30 ± 0.14
6.63 ± 0.02
5.32 ± 0.03
7.59 ± 0.03
M8.0
T HE C H I C AGO S URVEY
37
2MASS J
18253369-1214505
18264689-1207058
18311653-1009250
18320893-0939058
18334038-0828304
18335598-0821402
18464768-0241199
18473666-0156334
Data
M
M
M
M
M,P,P
M
M
M
P**
M
P*
P*
M
P
M
M
P*
M
P
P
ChI
J182538-1214_1
J182651-1206_4
J183116-1008_1
J183206-0938_1
J183345-0828_1
J183356-0822_2
J183356-0822_3
J184652-0240_1
J184738-0156_1
J184741-0219_3
J185608+0218_1
J185643+0220_2
J185750+0240_1
J190534+0659_1
J190749+0803_1
J190814+0832_2
J190818+0745_1
J194152+2251_2
J194310+2318_5
J194939+2631_1
J195006+2628_2
12.11 ± 0.02
8.21 ± 0.05
11.01 ± 0.06
> 20.3 ± 0.3
8.02 ± 0.04
> 19.1 ± 0.2
14.66 ± 0.11
> 8.04 ± 0.0
18.39 ± 0.11
10.49 ± 0.03
14.36 ± 0.04
17.05 ± 0.11
7.89 ± 0.02
17.38 ± 0.13
13.79 ± 0.11
14.32 ± 0.03
9.32 ± 0.03
14.85 ± 0.07
> 21.0 ± 0.3
8.44 ± 0.02
14.43 ± 0.11
16.61 ± 0.11
8.58 ± 0.03
19.76 ± 0.11
11.29 ± 0.03
15.17 ± 0.04
18.09 ± 0.11
8.03 ± 0.02
H
10.76 ± 0.02
12.10 ± 0.03
8.29 ± 0.04
5.40 ± 0.02
14.4 ± 0.11
J
11.27 ± 0.02
12.75 ± 0.03
9.09 ± 0.03
7.05 ± 0.02
15.71 ± 0.10
K
13.5 ± 0.11
13.74 ± 0.11
> 7.51 ± 0.0
17.77 ± 0.11
10.21 ± 0.03
14.04 ± 0.05
16.7 ± 0.12
7.84 ± 0.02
11.18 ± 0.03
7.64 ± 0.02
8.66 ± 0.04
18.46 ± 0.21
7.90 ± 0.02
10.59 ± 0.02
11.86 ± 0.03
7.63 ± 0.02
4.34 ± 0.03
13.68 ± 0.11
Near-Infrared Magnitudes
2009-04-13
2009-04-13
2007-07-29/31
2007-07-29
2009-04-13
2007-07-29
2009-04-14
2009-04-14
yyyy-mm-dd
PANIC date
062.9345+00.0934
059.4021-00.1526
042.4230+00.1975
041.7215-00.1814
040.7595+00.0667
035.5129-00.0030
023.5020+00.0505
030.0097-00.1937
030.7667-00.0346
023.3713+00.0549
019.1042+00.0722
019.3575-00.1313
021.6064-00.1970
SSTGLMC G
GLIMPSE name
13.28 ± 0.10
7.84 ± 0.04
10.06 ± 0.04
13.71 ± 0.09
7.19 ± 0.04
7.78 ± 0.05
10.44 ± 0.04
7.22 ± 0.05
13.36 ± 0.13
7.83 ± 0.05
10.06 ± 0.06
13.54 ± 0.12
7.26 ± 0.05
7.90 ± 0.04
10.39 ± 0.06
7.09 ± 0.05
13.00 ± 0.13
13.04 ± 0.09
M4.5
10.42 ± 0.06
11.41 ± 0.08
6.83 ± 0.06†
10.47 ± 0.07
11.46 ± 0.06
7.17 ± 0.04†
M3.6
7.80 ± 0.03
9.99 ± 0.06
7.14 ± 0.03
7.87 ± 0.03
10.12 ± 0.05
6.89 ± 0.03
5.48 ± 0.19†
12.49 ± 0.25
10.40 ± 0.09
11.25 ± 0.10
6.66 ± 0.03†
M5.8
GLIMPSE Magnitudesb
7.84 ± 0.03
9.87 ± 0.04
7.09 ± 0.03
7.80 ± 0.02
10.13 ± 0.07
6.95 ± 0.03
11.33 ± 0.20
6.32 ± 0.03†
M8.0
(which are more reliable). In these cases the GLIMPSE archive source’s names begin with SSTGLMA G.
with ** means that the counterpart has a low sigma detection of > 1.5σ for the respective background plus RMS estimate.
b
M3.6 , M4.5 , M5.8 , and M8.0 refer to the counterpart infrared magnitudes at 3.6, 4.5, 5.8, and 8.0 µm, respectively. Those magnitudes marked with † are from the GLIMPSE archives (more complete, less reliable) rather than the catalogs
obtained from different datasets. This order corresponds to the J, H and Ks magnitude order. Those datasets marked with * are likely blended or, particularly in the case of ChI J194152+2251_2, perhaps extended. Those datasets marked
Note. — The wavdetect position of ChI J165646-4239_1 and the position of the quoted 2MASS source agree within 4σ. We have listed this 2MASS source as a possible counterpart as it is considered to be the same as the quoted
GLIMPSE source, which does agree within 3σ of the wavdetect position. The quoted NIR magnitudes of ChI J181116-1828_2 and ChI J185643+0220_2, obtained with PANIC, are limits due to the counterparts being blended. The
H-band PANIC observation of ChI J194152+2251_2 took place on 2007-07-31, whereas the other bands were observed on 2007-07-29.
a
Data from which the counterpart near-infrared magnitudes were obtained. M = 2MASS Point Source Catalog (Skrutskie et al. 2006), P = PANIC Magellan observations. If three letters are listed this indicates that the magnitudes were
19431096+2317454
19080997+0831478
19081320+0743576
19053278+0659334
18560956+0217438
2MASS name
NIRa
ChIcAGO Source
Table 2 — Continued
38
T HE C H I C AGO S URVEY
39
Table 3
Quantile analysis power law interpolation and Cash statistics power law spectral fit to
ACIS Chandra detections of the ChIcAGO sources
Quantile absorbed power law interpolationa
ChIcAGO Source
Cash statistics absorbed power law fitb
χ2red
Γ
NH
Fx,abs
Fx,unabs
C
10.93 ± 0.90
0.3
8.45 ± 0.71
2.50 ± 0.27
0.17 ± 0.04
2.90 ± 0.20
3.62 ± 0.50
8.17 ± 1.11
3.35 ± 0.31
12.6 ± 1.03
5.97 ± 0.57
8.47 ± 0.71
4.46 ± 0.49
0.56 ± 0.12
11.47 ± 0.80
5.45 ± 0.76
11.73 ± 1.6
3.84 ± 0.35
14.19 ± 1.15
9.32 ± 0.9
0.9
0.6
+0.26
0.70−0.25
+1.06
4.98−0.94
+0.67
3.39−0.61
+0.28
−0.05−0.27
+0.43
2.35−0.39
+0.20
0.42−0.17
+1.25
4.53−1.07
+0.73
2.70−0.64
+0.32
0.49−0.27
+0.10
0.15−0.09
9.85+1.35
−1.15
2.38+0.45
−0.59
+1.15
5.55−1.90
+1.07
8.46−0.84
+0.38
2.86−0.46
11.17+1.29
−1.31
1802.71+4414.31
−1388.60
+157.69
177.46−139.42
+1.05
9.03−0.98
4.82+0.99
−1.22
0.5
1.0
0.6
1.2
1.0
0.9
0.4
0.6
1.4
0.8
0.7
0.31+0.48
−0.30
0.22+0.21
−0.20
1.00+5.60
−0.99
2.27 ± 0.30
2.5 ± 0.32
19.25 ± 2.37
2.98 ± 0.39
13.51 ± 1.73
19.91 ± 2.45
0.4
2.1
1.0
3.38+0.86
−0.65
0.31+1.60
−1.37
2.88+0.79
−0.63
0.16+0.18
−0.13
1.70+3.10
−1.69
0.26+0.19
−0.15
9.01 ± 0.73
2.10 ± 0.50
6.54 ± 0.61
27.22 ± 2.21
2.51 ± 0.59
19.03 ± 1.79
1.7
+0.28
2.72−0.27
+0.54
1.65−0.49
+0.83
0.75−0.75
+0.31
1.71−0.29
0.97+0.28
−0.27
1.29+0.31
−0.29
3.93+0.40
−0.36
1.28+0.44
−0.41
+0.79
3.17−0.60
+1.10
0.24−0.98
+1.98
4.89−1.45
+0.38
3.17−0.35
0.61 ± 0.11
+0.28
0.38−0.22
+2.02
2.59−1.53
0.31+0.13
−0.11
0.58+0.22
−0.19
0.38+0.18
−0.15
0.22 ± 0.06
0.22+0.21
−0.17
+0.12
0.07−0.07
14.01+8.49
−6.85
+0.31
0.37−0.23
0.23 ± 0.09
+0.36
2.88−0.33
+0.74
3.31−0.63
+2.09
7.62−2.68
+0.61
3.32−0.53
13.42+1.59
−1.83
6.48+1.14
−1.06
4.99+0.36
−0.39
2.37+0.49
−0.36
3.05+0.53
−0.59
+5.90
11.36−7.08
0.81+0.23
−0.22
+1.04
8.35−1.16
11.33+3.17
−3.55
5.99+1.39
−2.16
12.82+1.50
−3.94
5.01+0.72
−0.85
+2.16
16.43−1.68
8.66+1.01
−1.56
+18.76
27.34−13.30
3.18+0.35
−0.56
+4.82
7.05−2.67
29.98+6.53
−8.94
32.64+152.63
−26.84
+14.82
28.45−8.65
1.8
1.0
1.1
2.7
1.1
0.9
2.8
0.7
2.6
1.0
3.6
2.1
−0.75+0.49
−0.55
1.15+1.85
−1.03
6.83 ± 0.56
7.27 ± 0.60
0.6
6.60+11.9
−5.3
0.38+0.38
−0.25
0.28+0.30
−0.22
0.46+0.84
−0.40
2.30+2.00
−1.25
0.20+0.22
−0.15
5.40+4.60
−2.80
6.20+3.00
−2.00
2.20+2.20
−1.50
0.52+0.73
−0.50
0.20+0.31
−0.19
2.50+3.20
−1.59
0.70+0.50
−0.33
+0.48
0.67−0.31
2.8 ± 0.43
0.44 ± 0.06
0.55 ± 0.09
1.07 ± 0.16
2.86 ± 0.31
1.65 ± 0.24
1.16 ± 0.17
1.94 ± 0.22
2.77 ± 0.39
10.49 ± 0.98
0.35 ± 0.09
6.00 ± 0.94
3.79 ± 0.52
5.35 ± 0.62
4.11 ± 0.63
2.28 ± 0.34
2.11 ± 0.33
4.44 ± 0.68
4.01 ± 0.43
2.54 ± 0.37
14.45 ± 2.18
80.67 ± 9.02
7.66 ± 1.07
11.03 ± 1.03
1.48 ± 0.36
8.34 ± 1.30
5.20 ± 0.71
7.03 ± 0.81
0.14 ± 0.08
+0.08
0.14−0.07
2.19+1.12
−0.92
0.54+0.08
−0.07
+1.05
8.50−1.15
+0.38
2.64−0.29
+1.10
5.79−1.32
+0.11
2.07−0.18
12.81+2.24
−1.93
6.78+3.77
−2.33
7.09+0.84
−1.65
+49.73
67.55−32.05
1.7
3.3
1.4
1.8
0.14+1.93
−1.40
3.28+1.49
−1.00
+1.11
3.17−0.79
2.94+2.04
−1.28
0.84+0.75
−0.70
2.04+0.67
−0.47
2.84+1.86
−1.28
3.45+1.28
−0.93
2.00+1.38
−1.09
−0.16+0.55
−0.52
3.63+1.35
−1.07
0.77+1.11
−0.82
1.32+0.49
−0.37
+0.46
1.21−0.34
+0.33
2.09−0.31
+0.49
3.25−0.44
+0.41
−0.26−0.39
4.70+0.39
−0.37
0.4
0.6
0.6
0.2
3.5
1.63+0.52
−0.47
0.64+0.55
−0.51
2.17+0.60
−0.55
0.13+0.17
−0.13
2.40+1.18
−0.98
0.32+0.22
−0.19
+0.61
1.64−0.35
+0.57
3.02−1.03
1.64+0.35
−0.48
2.49+0.41
−0.54
4.28+0.52
−1.61
3.80+1.86
−1.69
1.4
0.6
3.3
0.7
1.6
0.5
2.71+0.72
−0.67
+0.68
1.52−0.61
+0.42
0.37−0.39
4.35+1.32
−1.15
+0.75
1.13−0.58
+0.77
1.62−0.65
1.96+0.40
−0.59
2.24+0.58
−0.88
10.12+1.67
−1.96
+17.88
23.39−13.91
5.14+1.53
−2.33
12.47+1.70
−1.92
1.7
2.3
0.5
1.1
1.5
1.2
−0.05+1.65
−0.84
0.14+0.38
−0.37
1.80+0.89
−0.70
2.28+0.70
−0.55
0.91+0.47
−0.46
+1.40
2.63−1.03
2.38+2.60
−1.75
1.28+1.28
−1.11
2.88+0.96
−0.70
2.35+1.79
−1.14
−1.62+1.86
−0.38
3.00+7.50
−2.66
0.55+0.33
−0.31
0.28+0.42
−0.27
4.80+1.80
−1.30
1.50+0.90
−0.71
2.60+2.00
−1.35
18.0+17.00
−10.20
1.80+2.40
−1.61
1.50+0.80
−0.56
12.0+9.00
−5.20
+12.00
1.00−0.99
1.96 ± 0.28
9.44 ± 0.61
0.34 ± 0.08
5.66 ± 0.61
29.85 ± 2.40
0.65 ± 0.10
2.06 ± 0.25
0.43 ± 0.11
4.14 ± 0.45
19.56 ± 1.76
2.57 ± 0.46
2.40 ± 0.34
10.13 ± 0.66
0.49 ± 0.12
28.9 ± 3.13
39.86 ± 3.20
4.04 ± 0.64
26.08 ± 3.14
0.69 ± 0.17
28.0 ± 3.02
178.36 ± 16.08
2.67 ± 0.47
1.9
1.0
+0.88
−0.18−0.77
+0.69
2.14−0.63
+0.52
1.61−0.48
+0.78
4.77−0.70
3.40+0.57
−0.52
+1.15
−0.08−0.99
0.43+0.24
−0.23
+2.19
1.24−1.24
+0.71
1.46−0.58
+0.59
1.38−0.50
1.44+0.34
−0.30
0.44+0.14
−0.13
2.98+4.05
−2.55
1.01+0.32
−0.28
+3.02
5.22−3.62
+0.89
2.97−0.94
+1.04
5.25−1.29
+0.09
0.45−0.13
+0.12
0.57−0.09
+0.79
1.25−0.96
9.37+0.71
−1.22
+3.14
6.48−3.06
+7.92
9.40−4.37
10.99+2.77
−4.17
+99.63
60.30−51.18
+3.81
4.49−2.67
1.84+0.74
−0.69
+1.04
10.83−1.16
0.7
2.0
1.6
3.4
2.2
2.5
1.7
1.4
0.7
3.28+0.86
−0.79
+0.36
0.86−0.35
8.15+2.26
−1.97
+0.58
1.81−0.51
5.33+1.11
−2.67
+3.69
33.04−7.94
+629.26
373.72−273.72
+5.54
47.45−11.41
1.7
1.4
1.0
+1.30
0.82−1.13
10.46+7.15
−5.41
+0.90
1.65−1.21
5.80+0.95
−1.38
1.2
1.0
1.2
+0.55
2.92−0.51
0.53+0.57
−0.53
+0.44
1.51−0.38
5.13+2.14
−1.75
+0.79
3.93−0.71
21.11+4.10
−8.53
+24.49
35.73−19.70
35.70+3.87
−12.23
1.8
2.2
0.00+0.63
−0.44
0.25+0.74
−0.58
2.28+1.35
−0.96
1.74+0.93
−0.75
2.66+0.62
−0.56
1.32+0.28
−0.25
0.38+0.56
−0.69
+0.69
0.67−0.49
0.97+1.53
−0.81
0.32+1.08
−0.31
0.52+0.68
−0.43
4.80+3.00
−2.00
0.73+0.37
−0.27
0.20+0.15
−0.12
0.82+0.58
−0.63
+1.90
2.30−1.15
3.27 ± 0.39
4.20 ± 0.63
0.73 ± 0.19
6.12 ± 0.64
0.9 ± 0.14
10.45 ± 0.89
6.07 ± 0.72
16.71 ± 1.57
3.59 ± 0.43
4.43 ± 0.66
1.70 ± 0.45
17.21 ± 1.80
3.41 ± 0.53
12.38 ± 1.05
6.84 ± 0.81
22.28 ± 2.09
1.3
0.5
3.83+0.44
−0.40
0.75+0.70
−0.64
0.31+0.60
−0.52
0.33 ± 0.08
3.22+1.83
−1.47
0.30+0.61
−0.30
+0.66
6.97−0.74
+0.53
3.03−1.35
4.01+0.78
−1.45
+47.69
50.56−22.77
4.97+0.63
−0.80
4.28+1.01
−0.97
1.8
1.6
0.4
0.2
1.0
0.7
0.3
0.9
0.75+0.55
−0.51
+0.86
3.22−0.74
+0.26
1.35−0.25
+0.50
0.36−0.46
+0.38
−0.10−0.35
2.73+1.24
−1.04
+0.36
0.74−0.29
+0.11
0.22−0.10
+0.72
0.91−0.55
+0.57
0.67−0.43
6.79+0.99
−1.89
0.73+0.18
−0.21
10.35+1.30
−1.38
+1.36
5.96−2.02
18.24+2.62
−4.08
10.52+1.11
−2.06
+6.28
5.83−3.54
12.91+1.55
−1.30
+1.39
7.02−1.88
20.06+2.18
−3.87
0.6
0.7
1.2
0.3
1.5
ChI
Γ
NH
Fx,abs
Fx,unabs
J143148-6021_3
J144547-5931_1
J144701-5919_1
J150436-5824_1
J154122-5522_1
J154557-5443_1
J155035-5408_3
J155831-5334_1
J162011-5002_1
J162046-4942_1
J165105-4403_1
J165217-4414_1
J165646-4239_1
J165646-4239_2
J165707-4255_1
J170017-4220_1
J170052-4210_1
J170444-4109_1
J170444-4109_2
J170536-4038_1
J171910-3652_2
J171922-3703_1
J172050-3710_1
J172550-3533_1
J172550-3533_2
J172550-3533_3
J172623-3516_1
J172642-3504_1
J173548-3207_1
J180857-2004_1
J180857-2004_2
J181116-1828_2
J181213-1842_7
J181213-1842_9
J181852-1559_2
J181915-1601_2
J181915-1601_3
J182435-1311_1
J182509-1253_1
J182509-1253_3
J182530-1144_2
J182651-1206_4
J183116-1008_1
J183206-0938_1
J183345-0828_1
J183356-0822_2
J183356-0822_3
J184652-0240_1
J184738-0156_1
J184741-0219_3
J185608+0218_1
J185643+0220_2
J185750+0240_1
J190534+0659_1
J190749+0803_1
J190814+0832_2
J190818+0745_1
J194152+2251_2
J194939+2631_1
0.91+0.44
−0.35
0.61+0.54
−0.34
9.12 ± 0.75
−0.37+0.17
−0.00
2.53+0.62
−0.49
+1.30
2.98−0.70
2.73+0.55
−0.46
1.70+0.72
−0.63
0.88+1.00
−1.00
+0.35
1.42−0.31
0.84+0.37
−0.31
1.63+0.47
−0.49
0.01+0.06
−0.00
0.14+0.14
−0.11
+0.19
0.29−0.17
0.67+0.24
−0.21
0.43+0.45
−0.34
2.50+2.8
−1.56
+0.15
0.12−0.10
0.34+0.36
−0.25
0.64+0.41
−0.34
1.49+0.79
−0.62
3.91+1.07
−1.25
−1.89+1.14
−0.10
1.0
40
Table 3 — Continued
Quantile absorbed power law interpolationa
ChIcAGO Source
ChI
Γ
NH
Fx,abs
Fx,unabs
Cash statistics absorbed power law fitb
χ2red
Γ
NH
Fx,abs
Fx,unabs
C
Note. — The quantile analysis spectral interpolation and Cash statistics spectral modeling are performed on those ChIcAGO sources with > 20 and > 50 X-ray counts, respectively.
a
The quantile analysis interpolated absorbed power law model parameters including the spectral index, Γ, and absorption column density NH (1022 cm−2 ), as well as the absorbed
and unabsorbed X-ray fluxes, Fx,abs and Fx,unabs (10−13 erg cm−2 s−1 ), respectively, in the 0.3 − 8.0 keV energy range. The quoted χ2red value is what is expected if these interpolated
spectral parameters are used to fit the X-ray spectrum of the source.
b
The absorbed power law fit model parameters using Cash (1979) statistics including the spectral index, Γ, and absorption column density NH (1022 cm−2 ), as well as the absorbed
and unabsorbed X-ray fluxes, Fx,abs and Fx,unabs (10−13 erg cm−2 s−1 ), respectively, in the 0.3 − 8.0 keV energy range. The quoted C value is the reduced Cash statistic, which is the
observed statistic divided by the number of degrees of freedom. A good fit is indicated by a C value of order 1.
T HE C H I C AGO S URVEY
41
Table 4
Quantile analysis Bremsstrahlung spectral interpolation and Cash Statistic
Bremsstrahlung spectral fit to ACIS Chandra detections of the ChIcAGO sources
Absorbed Bremsstrahlung interpolationa
ChIcAGO Source
Cash statistics absorbed Bremsstrahlung fitb
χ2red
kT
NH
Fx,abs
Fx,unabs
C
0.9
0.6
0.6
+0.37
1.01−0.23
+0.95
2.04−0.54
+1.68
2.62−0.80
3.27+0.86
−0.74
1.93+0.49
−0.43
0.05+0.06
−0.05
+0.68
1.93−1.24
+1.16
5.78−2.03
+0.45
2.46−0.47
+9.98
37.28−22.51
23.52+4.04
−7.51
+0.47
3.08−0.70
0.9
0.9
1.0
0.9
2.2
0.4
2.17+0.55
−0.38
+0.08
0.42−0.07
2.81+0.28
−0.37
+0.45
5.43−0.85
1.8
+16.53
8.37−3.50
0.78+0.14
−0.11
+0.24
0.87−0.16
+0.42
0.51−0.19
+0.42
1.54−0.30
+2.79
3.95−1.29
+0.25
1.23−0.20
+0.09
0.67−0.08
+0.09
0.24−0.08
0.03 ± 0.03
< 0.02
0.13+0.17
−0.13
0.03+0.06
−0.03
0.05+0.06
−0.05
< 0.03
0.24+0.05
−0.04
3.48+0.50
−0.61
5.06+0.53
−0.64
2.69+0.24
−0.53
0.84+0.18
−0.27
8.51+0.66
−0.88
+0.81
8.65−1.65
+0.30
2.59−0.26
+0.13
2.03−0.28
+0.56
4.48−0.89
6.62+0.49
−0.99
2.78+0.24
−0.57
+0.69
1.98−0.80
10.48+0.92
−1.02
+1.46
9.68−1.40
+0.25
2.71−0.20
+0.75
6.06−0.98
2.7
2.8
3.3
3.9
2.4
1.8
4.00
2.1
3.67+5.98
−1.59
+0.15
0.21−0.13
+0.42
1.57−0.70
2.13+0.68
−0.59
3.3
4.03+4.75
−1.50
+0.88
3.37−0.78
1.78+0.55
−1.13
+1.58
5.52−3.43
1.9
1.7
1.6
+17.68
5.44−2.61
0.74+0.21
−0.15
1.37+0.56
−0.34
+0.49
1.15−0.40
0.99+0.24
−0.21
0.20+0.09
−0.08
3.25+0.55
−0.99
0.44+0.08
−0.21
0.54+0.09
−0.19
5.92+1.18
−1.37
+0.91
3.90−2.11
+0.21
1.03−0.22
2.1
3.3
2.7
1.5
+2.26
2.96−0.96
6.37+1.54
−1.35
5.18+1.52
−2.86
+7.42
26.82−13.83
1.9
+1.06
2.21−0.59
1.14+0.31
−0.27
3.66+0.79
−1.46
+1.81
10.87−3.90
1.8
+0.21
0.96−0.16
0.10+0.05
−0.04
+0.72
6.82−0.83
11.02+1.91
−2.17
2.0
+1.00
1.46−0.48
+0.25
0.50−0.21
0.77
ChI
kT
NH
Fx,abs
Fx,unabs
J144519-5949_2
J144547-5931_1
J144701-5919_1
J154122-5522_1
J154557-5443_1
J154557-5443_2
J154557-5443_3
J155035-5408_1
J155035-5408_3
J155331-5347_1
J155831-5334_1
J162046-4942_1
J165646-4239_1
J165707-4255_1
J170052-4210_1
J170444-4109_1
J170536-4038_1
J171910-3652_2
J172050-3710_1
J172550-3533_2
J172550-3533_3
J172623-3516_1
J173548-3207_1
J175404-2553_3
J180857-2004_1
J180857-2004_2
J181116-1828_2
J181213-1842_9
J181915-1601_2
J182435-1311_1
J182509-1253_1
J182538-1214_1
J182651-1206_4
J183116-1008_1
J183345-0828_1
J183356-0822_2
J184652-0240_1
J184738-0156_1
J185608+0218_1
J190534+0659_1
J190814+0832_2
J194310+2318_5
J195006+2628_2
1.38+2.15
−0.65
0.84+0.30
−0.21
1.00+0.70
−0.39
1.88+0.96
−0.70
1.38+1.32
−0.73
1.77+96.43
−1.33
0.10+0.30
−0.00
0.35+0.18
−0.18
2.14+0.91
−0.72
0.31+0.31
−0.16
+89.16
9.04−5.99
4.80+3.60
−2.2
4.10+1.20
−0.9
3.50+1.90
−1.2
0.04+0.09
−0.03
0.14+0.15
−0.1
24.0+46.0
−15.8
0.97+1.23
−0.88
0.14+0.38
−0.14
0.43+0.21
−0.1
0.70+0.85
−0.39
0.34+0.30
−0.22
2.17 ± 0.44
2.56 ± 0.31
5.49 ± 0.60
2.35 ± 0.26
0.16 ± 0.03
0.63 ± 0.16
0.11 ± 0.03
0.18 ± 0.05
2.73 ± 0.19
1.25 ± 0.15
3.54 ± 0.49
21.59 ± 4.37
57.74 ± 6.95
74.01 ± 8.12
2.72 ± 0.3
0.25 ± 0.05
17.65 ± 4.49
224.95 ± 51.46
0.56 ± 0.14
5.29 ± 0.37
30.92 ± 3.67
4.73 ± 0.66
0.35+0.13
−0.10
0.71+0.21
−0.31
0.31+0.35
−0.16
0.97+0.28
−0.29
1.46+1.11
−0.55
0.17+0.07
−0.06
0.38+0.08
−0.06
+1.35
1.14−0.55
1.28+1.14
−0.56
1.56+6.01
−1.10
4.00+6.00
−2.30
2.56+95.64
−1.85
+19.41
3.19−1.77
2.21+1.68
−0.82
6.52+91.68
−4.45
0.84+0.79
−0.49
0.25+0.15
−0.10
0.05+0.16
−0.04
0.25+0.45
−0.22
0.01+0.10
0.00
0.13+0.14
−0.10
0.61+0.39
−0.24
0.37+0.09
−0.09
+0.25
0.20−0.16
0.10+0.21
−0.09
0.28+0.69
−0.26
0.12+0.21
−0.09
33.00+40.00
−18.00
4.40+3.20
−2.00
4.90+1.90
−1.40
1.85+1.55
−0.85
0.04+0.27
−0.03
4.06 ± 0.25
2.53 ± 0.32
0.84 ± 0.14
9.28 ± 0.75
6.09 ± 0.57
1.81 ± 0.17
1.77 ± 0.10
0.41 ± 0.06
0.55 ± 0.09
1.0 ± 0.15
1.58 ± 0.23
1.34 ± 0.27
1.12 ± 0.17
1.88 ± 0.21
2.7 ± 0.38
0.35 ± 0.09
20.59 ± 1.26
3.39 ± 0.43
4.93 ± 0.82
9.85 ± 0.80
9.33 ± 0.88
136.22 ± 12.59
12.78 ± 0.72
0.81 ± 0.12
0.79 ± 0.12
1.93 ± 0.29
1.95 ± 0.29
28.13 ± 5.69
4.19 ± 0.63
10.23 ± 1.14
5.36 ± 0.75
0.45 ± 0.11
1.8
2.1
0.84+0.19
−0.17
0.76+0.38
−0.23
0.38+0.90
−0.26
+91.89
6.31−4.17
5.26+7.89
−2.28
3.26+13.04
−1.77
+91.89
6.31−4.64
2.21+2.00
−0.86
5.47+92.73
−3.33
0.42+0.17
−0.11
3.12+41.53
−1.91
2.21+1.75
−0.72
0.55+0.29
−0.25
0.48+1.01
−0.32
0.82+0.18
−0.15
0.26+0.17
−0.12
0.37+1.13
−0.36
0.20+0.28
−0.19
4.10+1.30
−1.00
2.00+1.40
−0.90
16.0+13.0
−6.6
1.10+0.55
−0.37
11.0+6.00
−4.20
0.31+0.15
−0.12
0.37+0.45
−0.30
0.52+0.27
−0.19
0.12+0.22
−0.1
0.29+0.81
−0.28
0.47 ± 0.05
0.49 ± 0.05
0.52 ± 0.10
0.32 ± 0.08
5.55 ± 0.60
0.62 ± 0.10
2.05 ± 0.25
3.9 ± 0.42
19.34 ± 1.74
5.66 ± 0.41
0.69 ± 0.18
0.84 ± 0.13
0.69 ± 0.13
0.22 ± 0.04
2.54 ± 0.27
1.4 ± 0.15
3.86 ± 0.72
0.42 ± 0.10
15.35 ± 1.67
1.64 ± 0.26
10.44 ± 1.26
10.29 ± 1.11
83.9 ± 7.56
30.15 ± 2.16
1.12 ± 0.30
1.71 ± 0.26
1.42 ± 0.26
0.97 ± 0.20
1.8
1.1
1.1
1.1
0.6
0.6
3.6
0.6
1.5
1.0
0.9
1.2
1.3
0.8
0.4
Note. — The quantile analysis spectral interpolation and Cash statistics spectral modeling are performed on those ChIcAGO sources with > 20 and > 50 X-ray counts, respectively.
The CIAO task sample_flux failed for ChI J190814+0832_2 and so the quoted flux is taken from the best fit model parameters.
a
The quantile analysis interpolated absorbed thermal bremsstrahlung model parameters including the temperature, kT (keV), and absorption column density NH (1022 cm−2 ), as well
as the absorbed and unabsorbed X-ray fluxes, Fx,abs and Fx,unabs (10−13 erg cm−2 s−1 ), respectively, in the 0.3 − 8.0 keV energy range. The quoted χ2red value is what is expected if these
interpolated spectral parameters are used to fit the X-ray spectrum of the source.
b
The absorbed thermal bremsstrahlung fit model parameters using Cash (1979) statistics including the temperature, kT (keV), and absorption column density NH (1022 cm−2 ), as well
as the absorbed and unabsorbed X-ray fluxes, Fx,abs and Fx,unabs (10−13 erg cm−2 s−1 ), respectively, in the 0.3 − 8.0 keV energy range. The quoted C value is the reduced Cash statistic,
which is the observed statistic divided by the number of degrees of freedom. A good fit is indicated by a C value of order 1.
42
Table 5
Properties of optical counterparts, where they exist, for all ChIcAGO sources with > 20
X-ray counts
ChIcAGO Source
USNO Name
Opticala
ChI
USNO-B1.0
Data Source
B
V
R
I
yyyy-mm-dd
J143148-6021_3
J144042-6001_1
J144547-5931_1
J144701-5919_1
J154122-5522_1
J154557-5443_1
J154557-5443_3
J155035-5408_1
J155035-5408_3
J155331-5347_1
J155831-5334_1
J162046-4942_1
J163252-4746_2
J163751-4656_1
J165217-4414_1
J165420-4337_1
J165646-4239_1
J165646-4239_2
J165707-4255_1
J170017-4220_1
J170052-4210_1
J170444-4109_1
J170536-4038_1
J172050-3710_1
J172550-3533_2
J172550-3533_3
J172623-3516_1
J172642-3540_1
J173548-3207_1
J181116-1828_2
J181213-1842_7
J181213-1842_9
J181915-1601_2
J182435-1311_1
J182509-1253_1
J182538-1214_1
J182651-1206_4
J183116-1008_1
J183206-0938_1
J184652-0240_1
J185608+0218_1
J190534+0659_1
J190814+0832_2
J190818+0745_1
J194310+2318_5
J194939+2631_1
0296-0521275
0299-0503336
0304-0487344
0306-0492632
0346-0518164
0352-0535858
0352-0535969
0358-0537979
0358-0538167
0361-0529851
0364-0530109
0402-0531543
U,A,A,A
U
U
U
U
U
U
U
U
U
U
U
A
U
U,A,A,A
U,A,A,A
U
A
U
I,A,A,A
U
U
U
U
U
U
U
U
U
A(blend)
I
U
U
U
U
U
U
U
U
U
U
U
U
U
U
U,I,I,NA
19.71 ± 0.3
10.26 ± 0.3
20.54 ± 0.3
20.49 ± 0.03
19.31 ± 0.03
9.36 ± 0.3
15.79 ± 0.3
16.61 ± 0.3
11.87 ± 0.3
15.10 ± 0.3
16.51 ± 0.3
10.71 ± 0.3
13.96 ± 0.3
12.93 ± 0.3
16.37 ± 0.3
12.48 ± 0.3
> 25
14.94 ± 0.3
18.74 ± 0.03
19.01 ± 0.03
12.46 ± 0.3
21.76 ± 0.05
12.37 ± 0.3
> 25
13.57 ± 0.3
15.07 ± 0.3
10.89 ± 0.3
11.62 ± 0.3
14.84 ± 0.3
11.16 ± 0.3
11.86 ± 0.3
9.98 ± 0.3
14.67 ± 0.3
18.93 ± 0.03
18.27 ± 0.03
8.99 ± 0.3
12.30 ± 0.3
12.95 ± 0.3
10.87 ± 0.3
14.67 ± 0.3
15.42 ± 0.3
10.43 ± 0.3
13.09 ± 0.3
12.74 ± 0.3
16.15 ± 0.3
10.71 ± 0.3
21.93 ± 0.05
15.07 ± 0.3
17.80 ± 0.03
17.82 ± 0.03
10.89 ± 0.3
20.83 ± 0.04
11.04 ± 0.3
> 23.4± 0.3
11.83 ± 0.3
13.01 ± 0.3
10.33 ± 0.3
11.47 ± 0.3
14.97 ± 0.3
10.89 ± 0.3
10.82 ± 0.3
9.16 ± 0.3
14.45 ± 0.3
17.84 ± 0.03
2008-05-13
0430-0573746
0457-0509597
0463-0473777
0473-0602564
0470-0567106
0478-0576746
0488-0491640
0493-0497837
0528-0624586
0544-0498651
0544-0498592
0547-0493410
0543-0502139
0578-0723476
0713-0551349
0739-0563199
0768-0532899
0771-0546066
0777-0567961
0778-0569793
0798-0402571
0803-0434604
0873-0550754
0922-0521590
0969-0463844
0985-0428114
0977-0515881
1132-0447077
1165-0456015
Optical Magnitudesb
13.17 ± 0.3
16.16 ± 0.3
17.91 ± 0.3
11.40 ± 0.3
15.81 ± 0.3
14.38 ± 0.3
16.99 ± 0.3
15.03 ± 0.3
> 25
15.27 ± 0.3
19.03 ± 0.3
17.62 ± 0.3
14.49 ± 0.3
19.73 ± 0.03
19.88 ± 0.03
22.69 ± 0.06
14.15 ± 0.3
> 23.5± 0.3
15.02 ± 0.3
16.68 ± 0.3
11.65 ± 0.3
11.97 ± 0.3
16.04 ± 0.3
11.82 ± 0.3
14.26 ± 0.3
11.62 ± 0.3
15.19 ± 0.3
> 25
20.08 ± 0.03
> 23.5± 0.5
13.43 ± 0.3
16.15 ± 0.3
13.08 ± 0.3
12.64 ± 0.3
14.33 ± 0.3
16.62 ± 0.3
16.79 ± 0.3
19.50 ± 0.3
10.36 ± 0.3
14.67 ± 0.3
16.05 ± 0.3
18.04 ± 0.3
9.63 ± 0.3
20.20 ± 0.3
20.1 ± 0.1
13.66 ± 0.3
11.01 ± 0.3
11.36 ± 0.3
13.00 ± 0.3
13.97 ± 0.3
13.38 ± 0.3
16.59 ± 0.3
15.44 ± 0.3
9.48 ± 0.3
11.98 ± 0.3
14.32 ± 0.3
16.74 ± 0.3
9.08 ± 0.3
19.1 ± 0.1
MagIC or IMACS Datec
2008-05-13
2008-05-13
2008-05-13
2008-05-13
I:2008-07-30,A:2008-05-13
2008-05-13
2008-07-30
12.76 ± 0.3
11.23 ± 0.3
9.92 ± 0.3
10.74 ± 0.3
12.89 ± 0.3
14.10 ± 0.3
11.35 ± 0.3
12.41 ± 0.3
9.12 ± 0.3
10.46 ± 0.3
12.78 ± 0.3
16.54 ± 0.3
8.85 ± 0.3
2008-07-30
Note. — ChI J170017–4220_1 was observed with both MagIC and IMACS. The dates of both observations are listed and prefixed by the corresponding dataset symbol described
below. The MagIC observation of ChI J181116-1828_2 shows that it may be a blend.
a
Catalog or observations from which the counterpart optical magnitudes were obtained. U = USNO B1 Catalog (Monet et al. 2003), A = MagIC Magellan observations, I = IMACS
Magellan observations, NA = no data for the corresponding magnitude. If four symbols are listed this indicates that the magnitudes were obtained from different datasets. This order
corresponds to the B, V , R and I magnitude order.
b
The USNO-B1.0 B and R band magnitudes listed are the second epoch B and R magnitudes (Monet et al. 2003)
c
Date of the MagIC and IMACS observations: yyyy-mm-dd.
T HE C H I C AGO S URVEY
43
Table 6
The chance of a random association between the listed ChIcAGO sources (all of which
have > 20 X-ray counts) and a 2MASS and GLIMPSE source
ChIcAGO source
ChI
2MASS N(< Ks )a
(×10−2 )
J155831–5334_1
J163751–4656_1
J165420–4337_1
J172550–3533_2
J173548–3207_1
J181116–1828_2
J183345–0828_1
J190818+0745_1
1.76
1.67
GLIMPSE N(< M3.6 )b
(×10−2 )
1.08
1.22
3.16
2.29
1.71
3.02
3.15
1.25
1.17
Note. — Only those ChIcAGO sources where the chance of random alignment with a survey source is > 0.01 are listed.
a
b
Chance of finding a 2MASS source with a Ks magnitude brighter than the counterpart listed in Table 2 within the ChIcAGO source’s 95% position error circle.
Chance of finding a GLIMPSE source with a 3.6µm magnitude brighter than the counterpart listed in Table 2 within the ChIcAGO source’s 95% position error circle.
Table 7
Likely optical and infrared counterparts of secondary (< 20 X-ray counts) ChIcAGO
Sources
ChIcAGO Source
ChI
USNO Name
USNO-B1.0
offseta
(arcsec)
2MASS name
2MASS J
offseta
(arcsec)
GLIMPSE nameb
SSTGLMC G
offseta
(arcsec)
J143148-6021_1
J143148-6021_2
J143148-6021_4
J144519-5949_1
J144519-5949_4
J144519-5949_5
J144519-5949_6
J145732-5901_1
J150436-5824_2
J150436-5824_3
J151005-5824_4
J151005-5824_5
J151005-5824_9
J151005-5824_10
J151005-5824_11
J153751-5556_1
J153751-5556_2
J154122-5522_2
J154122-5522_3
J154557-5443_6
J154557-5443_7
J154905-5420_1
J154905-5420_10
J154905-5420_11
J154905-5420_3
J154905-5420_4
J154905-5420_5
J154905-5420_6
J154905-5420_8
J154951-5416_1
J155035-5408_2
J155831-5334_2
J162011-5002_2
J162208-5005_3
J162246-4946_2
J162246-4946_4
J163524-4728_3
J163524-4728_4
J165420-4337_2
J165707-4255_2
J165901-4208_1
J165901-4208_2
J165901-4208_3
J170017-4220_2
J170112-4212_1
J170555-4104_1
J170555-4104_2
J171715-3718_1
J171715-3718_2
J171910-3652_3
J171922-3703_2
0296-0521300
0296-0521279
0296-0521208
0.4
0.35
0.32
0301-0471052
0.36
0315-0471854
0.84
14315021-6022087
14314859-6021444
14314161-6019552
14451506-5949286
14451937-5948007
14445787-5950387
14450584-5949317
14573495-5859538
15043142-5823048
15045112-5824582
15100715-5826089
15100685-5825567
15095562-5826220
15095233-5827126
15100507-5826021
15375937-5554232
15373513-5556504
0.56
0.25
0.7
0.51
0.47
0.3
0.64
0.18
0.98
0.57
0.23
0.14
0.16
0.52
0.15
0.45
0.38
G315.0382+00.1212
G315.0377+00.1287
G315.0358+00.1622
G316.7879-00.0504
G316.8065-00.0321
G316.7471-00.0527
G316.7701-00.0429
G318.5603-00.0084
G319.6454+00.1008
G319.6676+00.0522
G320.2556-00.3078
0.41
0.36
0.56
0.61
0.64
0.66
0.78
0.22
1.11
0.67
0.62
G320.2324-00.2984
G320.2189-00.3069
G320.2527-00.3040
G324.7982-00.2732
G324.7284-00.2727
G325.5315-00.1292
G325.4728-00.1194
0.74
0.46
0.39
0.29
0.13
0.55
0.49
15485853-5421473
15484845-5419001
15490739-5418534
15485233-5419128
15490492-5419300
15491154-5422275
0.43
0.26
0.09
0.26
0.14
0.43
0.28
0.14
0.59
0.23
0.38
0.27
0.33
0.23
0.44
0.65
0.33
G326.9824-00.0001
G326.9922+00.0514
G327.0294+00.0242
G326.9974+00.0428
G327.0183+00.0200
G327.0002-00.0285
G326.9922-00.0152
G327.0269+00.0141*
G327.1384-00.0116*
G327.2937+00.0181
G328.6013-00.3046
G333.4207+00.0715
G333.6115-00.1955
G333.9125-00.0647
G333.9312-00.0730
G336.9720+00.0028
G337.0012+00.0305
G342.1074-00.0150
G342.9629+00.0301
G343.8034+00.2822
G343.7873+00.2447
G343.7945+00.2579
G343.8034-00.0300
G343.9738-00.1029
G345.4011-00.0573
G345.3981-00.0601
G349.7655+00.4099*
G349.7829+00.3556
G350.3546+00.2705
G350.2423+00.1677
0.54
0.45
0.2
0.19
0.19
0.54
0.78
0.62
0.46
0.37
0.71
0.36
0.53
0.4
0.69
0.07
0.39
0.71
0.44
0.34
0.44
0.13
0.19
0.23
0.17
0.41
0.59
0.71
1.02
0.33
0340-0505998
0340-0505789
0.41
0.37
0352-0535841
0353-0529489
0.33
1.13
0356-0527966
0356-0528195
0.53
0.62
0356-0528174
0.54
0357-0538762
0358-0538121
0364-0530387
0399-0531568
0.27
0.35
0.28
0.16
0424-0650841
0425-0649089
0463-0473953
0470-0567346
0.26
0.39
0.73
0.62
15495168-5416297
15503372-5409160
15584724-5334064
16200603-5001406
16220699-5004580
16225165-4946377
16225873-4946109
16352088-4730567
16352057-4728317
16543480-4338027
16571994-4256206
0478-0574898
0476-0587932
0.2
0.03
16591198-4209350
16591006-4208451
17002524-4219003
0.34
0.08
0.08
0489-0494967
0489-0494969
0527-0619568
0.4
0.28
0.72
0531-0542255
0529-0602946
0.11
0.11
17054550-4104024
17054564-4104172
17170761-3716139
17172402-3717160
17192403-3652095
17192991-3701128
0.28
0.37
0.38
0.5
0.41
0.22
44
Table 7 — Continued
ChIcAGO Source
ChI
J171922-3703_4
J172623-3516_2
J172642-3504_3
J172642-3504_4
J172642-3504_5
J173628-3141_1
J180857-2004_3
J181033-1917_1
J181116-1828_1
J181116-1828_3
J181116-1828_4
J181213-1842_1
J181213-1842_2
J181213-1842_4
J181213-1842_5
J181213-1842_6
J181213-1842_8
J181705-1607_2
J181705-1607_4
J181705-1607_5
J181705-1607_7
J181852-1559_1
J181852-1559_3
J181917-1548_1
J182509-1253_2
J182651-1206_1
J183116-1008_2
J183116-1008_3
J183345-0828_2
J183356-0822_1
J183356-0822_6
J183356-0822_7
J183518-0754_1
J184008-0543_1
J184400-0355_1
J184652-0240_2
J184741-0219_2
J184741-0219_4
J184741-0219_5
J185643+0220_1
J190814+0832_1
J190814+0832_3
J190818+0745_3
J194152+2251_1
J194152+2251_3
J194310+2318_1
J194310+2318_2
J194310+2318_3
J194310+2318_4
J194310+2318_6
J194310+2318_7
J194310+2318_8
J194310+2318_10
J194332+2323_1
J194332+2323_2
J194332+2323_3
J194332+2323_4
J194332+2323_5
J194332+2323_6
J194332+2323_8
J194622+2436_1
J194622+2436_2
J194622+2436_3
J195006+2628_1
J195006+2628_3
J195006+2628_4
J195006+2628_5
a
b
offseta
(arcsec)
2MASS name
2MASS J
offseta
(arcsec)
GLIMPSE nameb
SSTGLMC G
offseta
(arcsec)
0.44
0.73
0.62
0.71
0.3
0.48
0.28
0.8
G350.1967+00.1702
G352.4885+00.0118
0549-0511010
0549-0510994
17192143-3703225
17262588-3515229
17264746-3504569
17264522-3502047
0583-0582872
0699-0558263
0.43
0.25
0715-0555726
0.14
0714-0538112
0.39
17362729-3141234
18090897-2004218
18103278-1917550
18112081-1828199
18110974-1827473
18111909-1830479
18122087-1844028
0.2
0.41
0.49
0.17
0.44
0.47
0.12
0713-0551671
0713-0551557
0713-0551321
0712-0536482
0712-0537442
0738-0565615
0738-0565492
0739-0559943
0738-0565550
0740-0564778
0740-0564744
0.24
0.45
0.4
0.4
0.58
0.57
0.63
0.14
0.44
0.27
0.23
18121282-1841259
0.66
G352.7090+00.0808
G352.6923+00.1040
G356.6169+00.2196
G010.3480-00.1793
G011.1845-00.0929
G011.9999+00.1394
G011.9868+00.1823
G011.9605+00.1256
G011.8843-00.1943
G011.9377-00.1384
G011.9073-00.1456
0.47
0.08
0.1
0.35
0.66
0.3
0.3
0.39
0.24
0.26
0.29
0771-0545940
0779-0556414
0798-0402569
0798-0402703
0815-0416246
0816-0437498
0816-0437875
0816-0437882
0820-0496843
0.28
0.48
0.37
0.31
0.31
0.42
0.81
0.72
0.22
18120510-1843248
18122472-1842024
18170377-1606272
18165657-1608235
18170585-1605576
18165970-1606182
18185174-1559403
18185004-1559157
18190851-1549270
18250314-1252109
0.76
0.47
0.3
0.36
0.2
0.18
0.22
0.8
0.45
0.27
18311645-1009105
18312100-1007598
18334527-0825192
18335034-0823032
0.3
0.34
0.51
0.39
G011.8637-00.1347
G011.9210-00.1916
G014.7290+00.0720
G014.6869+00.0820
G014.7402+00.0686
G014.7235+00.0876
G015.0335-00.2550
G015.0364-00.2457
G015.2154-00.2336
G018.4960-00.1086
G019.4011-00.1473
G021.6098-00.1949
G021.6358-00.2024
G023.4277+00.0616
G023.4708+00.0605
1.09
0.36
0.12
0.39
0.38
0.38
0.14
0.84
0.19
0.09
0.31
0.07
0.19
0.42
0.35
18340563-0821033
18352446-0754383
0.32
0.38
0860-0388202
0873-0550942
0876-0581370
0.42
0.5
0.34
0876-0581506
0923-0533662
0.24
0.17
0985-0428173
0.46
18440331-0358188
18465626-0239530
18473651-0219323
18474299-0218227
18474431-0219167
18564801+0218361
19081119+0829537
19081590+0832408
0.5
0.27
0.18
0.51
0.34
0.49
0.67
0.24
G024.0701-00.0659
G026.5331-00.0987
G028.5561-00.1712
G030.0475-00.2144
G030.4257-00.2088
G030.4552-00.2240
G030.4444-00.2357
G035.5989-00.1389
G042.3972+00.1784
G042.4474+00.1826
G041.7964-00.1868
0.7
0.13
0.33
0.41
0.24
0.38
0.14
0.55
0.73
0.31
0.78
1128-0498149
1129-0484063
1132-0446999
1132-0447018
1133-0422179
1133-0422272
1133-0422204
1133-0422314
0.81
0.26
0.24
0.8
0.52
0.5
0.21
0.17
1133-0422494
1134-0415530
0.51
0.45
19415297+2254177
19430677+2316122
19430779+2317032
19430494+2318339
19431133+2320391
19430704+2318318
19431451+2320165
19431304+2317250
19430845+2318172
19432717+2323314
0.67
0.25
0.26
0.16
0.27
0.33
0.21
0.26
0.16
0.26
G058.9142-00.0873
G059.3716-00.1515
G059.3858-00.1479
G059.4023-00.1258
G059.4446-00.1298
G059.4058-00.1331
G059.4452-00.1435
G059.4011-00.1623
G059.4050-00.1398
G059.5163-00.1585
0.73
0.48
0.33
0.22
0.15
0.19
0.02
0.33
0.29
0.3
1134-0415508
1134-0415545
1134-0415461
0.19
0.27
0.2
19434329+2324562
19432977+2325098
19433302+2326247
19432305+2325174
0.4
0.25
0.14
0.08
1145-0435437
1146-0434793
1146-0434550
1164-0455522
0.25
0.48
1.05
0.46
1164-0455331
1164-0455237
0.89
0.28
19462497+2435462
19463435+2437058
19461529+2438323
19501612+2627172
19500352+2627436
19500525+2628178
19500110+2629342
0.58
0.41
0.39
0.43
0.39
0.36
0.11
G059.5674-00.2002
G059.5450-00.1535
G059.5692-00.1539
G059.5340-00.1301
G059.5078-00.1462
G060.8974-00.1421
G060.9345-00.1617
G060.9190-00.0872
G062.9404+00.0480
G062.9228+00.0922
G062.9343+00.0915
G062.9447+00.1156
0.29
0.16
0.18
0.23
0.91
0.69
0.58
0.52
0.23
0.15
0.4
0.24
USNO Name
USNO-B1.0
The offset, in arcseconds, between the catalogs and ChIcAGO source position for the likely USNO B1, 2MASS and GLIMPSE counterparts, respectively.
Those GLIMPSE counterpart names marked with a * are from the archives (more complete, less reliable) rather than the catalogs (more reliable). In these cases the archival
GLIMPSE source’s names begins with “SSTGLMA G.”
T HE C H I C AGO S URVEY
45
Table 8
Summary of the fraction of ChIcAGO sources with a coincident cataloged source from
2MASS, GLIMPSE and USNO B1. These fractions are for the total number of ChIcAGO
sources and for the ChIcAGO sources with > 20 X-ray counts.
ChIcAGO source
samples
2MASS fraction
(%)
GLIMPSE fraction
(%)
USNO B1 fraction
(%)
Total (253 sources)
> 20 X-ray counts (74 sources)
57
59
61
61
47
55
Table 9
Radio counterparts to ChIcAGO Sources
ChIcAGO Source (ChI)a
J144042–6001_1
J144519–5949_(1-6)
J144701–5919_1
J145732–5901_(1-2)
J151005–5824_(1-11)
J153818–5541_1
J154905–5420_(1-11)
J155331–5347_1
J155331–5347_2
J162208–5005_(1-3)
J163252–4746_1
J163252–4746_2
J163751–4656_1
J165217–4414_1
J165420–4337_1
J165420–4337_2
J165646–4239_(1-2)
J165707–4255_(1-2)
J170052–4210_1
J172550–3533_(1-3)
J180857–2004_1,2
J181116–1828_5
J181213–1842_1,8
J181213–1842_2,5
J181705–1607_(1-7)
J182435–1311_(1-4)
J182538–1214_1
J183206–0938_1
J183356–0822_6,7
J184400–0355_1
J184447–0305_1
J184738–0156_1
J184741–0219_3
J194310+2318_(1-10)
J194332+2323_(1-8)
J194622+2436_1
J195006+2628_(1-5)
Surveyb
Radio source
Typec
Locationd
Referencee
MGPS
MGPS
ATCA
MGPS
MGPS
ATCA
MGPS
ATCA
ATCA
MGPS
ATCA
ATCA
ATCA
MGPS
ATCA
ATCA
MGPS
MGPS
ATCA
MGPS
90, MAGPIS
MAGPIS
90, MAGPIS
90, MAGPIS
90, MAGPIS
90, MAGPIS
90, MAGPIS
MAGPIS
MAGPIS
MAGPIS
MAGPIS
MAGPIS
MAGPIS
VGPS
VGPS
VGPS
VGPS
SNR G316.3–0.0
GAL 316.8-00.1
AX J144701–5919
SNR G318.2+0.1
G320.3–0.3
SNR
H II
MS
SNR
H II
ND
H II
ND
ND
H II
ND
CWB
ND
Arc
ND
ND
IRDC
Arc
ND
Arc
D
AGN
SNR
SNR
D
SNR
SNR
CWB
SNR
SNR
SNR
CWB
AGN
H II
H II
Com
H II
L
C
C
L
C
1
2
3
4,5
6
7
8
7
7
6
7
3
7
G326.96+0.03
G333.6–0.2
AX J163252–4746
uncataloged
SDC G343.306+0.161
uncataloged
uncataloged
MAGPIS 10.3139–01417
MAGPIS 11.97095+0.19155
SNR G11.8–0.2
SNR G12.0–0.1
MAGPIS 14.6167+0.0667
SNR G18.1–0.1
SNR G19.1+0.2
MAGPIS 22.15394–0.15414
SNR 23.5667–0.0333
SNR G28.6–0.1
SNR 29.3667+0.1000
NVSS 184736–015632
MAGPIS 30.43741–0.20625
G59.5–0.2
G59.5–0.2
NVSS 194620+243514
G62.9+0.1
A
C
C
C
C
C
7
7
9
7
L
C
K
L
A
L
C
L
C
L
L
C
C
K
C
C
L
C
10
10
11
12
10
10,11
11
10,13
10
14
10
3,15
10
6
6
15
6,16
References. — 1: Shaver & Goss (1970); 2: Haverkorn et al. (2006); 3: Anderson et al. (2011); 4: Whiteoak & Green (1996); 5: Bocchino et al. (2001); 6: Kuchar & Clark (1997);
7: This paper; 8: McClure-Griffiths et al. (2001); 9: Peretto & Fuller (2009); 10: Helfand et al. (2006); 11: Brogan et al. (2006); 12: Caswell et al. (1975); 13: Motch et al. (2010);
14: Helfand et al. (1989); 15: Condon et al. (1998); 16: Ramos-Larios et al. (2010)
a
The names of the ChIcAGO sources with radio counterparts. If all the ChIcAGO sources in a Chandra observation of an AGPS source are coincident with the radio counterpart,
then the range of suffixes are listed in parentheses. If only a subset of the ChIcAGO sources detected in a given Chandra observation are coincident with the radio counterpart, then
only those suffixes are listed.
b
The radio Galactic plane surveys or observations visually inspected- MGPS: Molonglo Galactic Plane Survey, 90: 90cm Multi-configuration Very Large Array survey of the Galactic
Plane, MAGPIS: The Multi-Array Galactic Plane Imaging Survey, VGPS: VLA Galactic Plane Survey. ATCA: Australia Telescope Compact Array observations obtained for radio
follow-up of ChIcAGO sources (see Sections 2.4.2 and 3.4).
c
Type of radio source- SNR: Supernova Remnant; H II: H II region; MS: Massive star; CWB: colliding-wind binary; IRDC: Infrared Dark Cloud; AGN: Likely Active Galactic
Nuclei based on a core-lobe morphology; D: Diffuse; Arc: Diffuse emission with an arc or shell morphology; Com: Compact; ND: No detection in the case of the ATCA observations.
d
Position of the ChIcAGO source relative to the radio source- C: Coincident, A: Adjacent; L: Limb (usually the limb or edge of a SNR, arc/shell structured diffuse emission or H II
region); K: Core of a possible AGN given the apparent core-lobe morphology.
e
Many additional references to the SNRs are compiled in Green (2009).
46
Table 10
The chance of a random association between the listed ChIcAGO sources coincident with
SNRs and a USNO B1 and GLIMPSE source
ChIcAGO source
ChI
J181213-1842_1
J181213-1842_2
J181213-1842_5
J182435-1311_1
J183356-0822_6
USNO B1 N(< R)a
(×10−2 )
3.05
4.04
GLIMPSE N(< M3.6 )b
(×10−2 )
1.15
7.15
3.17
1.68
Note. — Only those ChIcAGO sources where the chance of random alignment with a survey source is > 0.01 are listed.
a
b
Chance of finding a USNO source with a R magnitude brighter than the counterpart listed in Table 7 within the ChIcAGO source’s 95% position error circle.
Chance of finding a GLIMPSE source with a 3.6µm magnitude brighter than the counterpart listed in Tables 2 or 7 within the ChIcAGO source’s 95% position error circle.
+3.60
5.00−2.10
+51.00
22.00−15.00
+0.68
0.14−0.14
7.60+27.40
−4.60
+0.00
2.80−2.07
+1.30
1.60−1.35
2.20+−0.10
−1.53
+0.00
1.80−1.50
2.50+10.50
−2.49
+11.00
21.00−17.00
+28.00
33.00−21.00
+0.25
0.010.00
+1.00
1.20−1.16
+0.87
0.38−0.38
+12.50
11.50−5.60
+3.30
2.30−0.80
+39.50
15.50−9.50
+1.29
0.010.00
+0.42
0.010.00
+0.35
1.05−1.04
+1.10
1.20−1.19
+0.60
0.010.00
+0.66
0.010.00
0.46+1.39
−0.45
2.40+3.60
−1.10
+2.30
2.60−1.40
+1.04
0.010.00
+0.00
0.67−0.66
+−0.03
0.76−0.75
+3.85
1.75−1.05
1.60+10.90
−1.59
+0.26
0.94−0.93
+1.40
1.70−1.69
+1.52
0.13−0.12
+4.60
3.00−1.30
1.15+10.35
−1.14
+2.49
0.010.00
+.15
0.58−0.57
+2.35
1.25−0.73
+1.49
0.010.00
+1.87
0.23−0.22
+3.50
2.10−1.37
+1.35
1.55−1.54
1.52+1.38
−0.73
0.78+2.69
−0.57
J144519-5949_2
J144519-5949_3
J144519-5949_5
J151005-5824_1
J151005-5824_2
J151005-5824_3
J151005-5824_4
J151005-5824_5
J151005-5824_6
J151005-5824_7
J151005-5824_8
J151005-5824_9
J151005-5824_10
J151005-5824_11
J154905-5420_1
J154905-5420_2
J154905-5420_3
J154905-5420_4
J154905-5420_5
J154905-5420_7
J154905-5420_8
J154905-5420_9
J154905-5420_10
J154905-5420_11
J162208-5005_1
J162208-5005_3
J194310+2318_1
J194310+2318_4
J194310+2318_5
J194310+2318_6
J194310+2318_7
J194310+2318_8
J194310+2318_9
J194332+2323_1
J194332+2323_3
J194332+2323_5
J194332+2323_6
J194332+2323_7
J195006+2628_1
J195006+2628_2
J195006+2628_3
J195006+2628_4
J195006+2628_5
> 1.94
0.90+1.80
−0.77
82.45
0.21+1.42
−0.11
82.45
82.45
> 0.1
> 2.21
0.17+0.33
−0.07
> 2.49
> 5.26
> 0.1
0.61+0.81
−0.33
> 2.63
0.74+1.54
−0.56
1.80+3.04
−1.69
> 0.1
> 16.3
> 4.63
> 0.1
> 0.1
> 0.63
> 1.91
> 6.52
2.28+6.97
−1.86
0.12+19.33
−0.02
0.14+3.33
−0.03
0.76+1.38
−0.62
> 0.19
82.45
0.10+1.28
0.00
2.91+7.09
−2.56
0.22+0.33
−0.11
> 0.1
> 0.1
0.15+0.55
−0.05
0.10+0.04
0.00
1.74+2.02
−1.62
2.70+16.75
−2.59
0.40+1.23
−0.29
0.11+1.76
−0.01
NH
kT
Fx,unabs
218.44 ± 44.20
7207.60 ± 2610.31
3.98 ± 2.71
47.76 ± 28.64
2.92 ± 1.45
65.24 ± 44.33
1.96 ± 1.18
1.76 ± 1.06
452.64 ± 182.20
36.97 ± 11.10
218762449.44 ± 108233831.76
0.42 ± 0.28
2.00 ± 0.99
0.79 ± 0.54
743.78 ± 340.69
6.63 ± 2.20
397.68 ± 270.25
0.41 ± 0.25
1.69 ± 0.72
2.66 ± 1.22
1.57 ± 1.07
0.71 ± 0.38
0.47 ± 0.32
2.05 ± 0.78
42.69 ± 11.74
11.30 ± 7.68
5.47 ± 1.50
253.21 ± 172.07
1446.16 ± 262.87
94.55 ± 24.98
909.74 ± 491.76
5.22 ± 3.55
18914.51 ± 11342.64
2.10 ± 0.69
1053.73 ± 569.60
24.79 ± 8.57
0.73 ± 0.39
51.52 ± 23.60
3815.10 ± 2062.27
2.83 ± 0.57
.88 ± .60
58.70 ± 31.73
5807.00 ± 2211.85
Fx,abs
23.70 ± 4.80
13.05 ± 4.73
3.37 ± 2.29
0.74 ± 0.45
1.72 ± 0.85
0.18 ± 0.12
1.21 ± 0.73
1.14 ± 0.68
0.44 ± 0.18
6.46 ± 1.94
0.96 ± 0.48
0.41 ± 0.28
1.39 ± 0.69
0.64 ± 0.43
1.49 ± 0.68
4.07 ± 1.35
0.99 ± 0.67
0.40 ± 0.24
1.66 ± 0.71
1.89 ± 0.87
1.09 ± 0.74
0.70 ± 0.38
0.46 ± 0.31
1.24 ± 0.47
23.73 ± 6.53
6.75 ± 4.59
5.31 ± 1.46
1.06 ± 0.72
5.97 ± 1.08
5.33 ± 1.41
1.70 ± 0.92
3.77 ± 2.56
0.99 ± 0.59
1.65 ± 0.55
0.64 ± 0.35
3.81 ± 1.32
0.70 ± 0.38
0.64 ± 0.29
0.70 ± 0.38
2.74 ± 0.55
0.61 ± 0.42
0.63 ± 0.34
0.74 ± 0.28
Absorbed Mekal interpolationa
ChI
ChIcAGO Source
2.8
2.8
2.8
4.7
4.7
4.7
4.7
4.7
4.7
4.7
4.7
4.7
4.7
4.7
3.7
3.7
3.7
3.7
3.7
3.7
3.7
3.7
3.7
3.7
3.1
3.1
2.6
2.6
2.6
2.6
2.6
2.6
2.6
2.6
2.6
2.6
2.6
2.6
2.3
2.3
2.3
2.3
2.3
(kpc)
1
1
1
2
2
2
2
2
2
2
2
2
2
2
3
3
3
3
3
3
3
3
3
3
2
2
2
2
2
2
2
2
2
2
2
2
2
2
4
4
4
4
4
Ref
Distanceb
32.35
32.09
31.50
31.29
31.66
30.68
31.51
31.48
31.07
32.23
31.41
31.04
31.56
31.23
31.39
31.82
31.21
30.82
31.44
31.49
31.25
31.06
30.88
31.31
32.44
31.89
31.63
30.93
31.68
31.63
31.14
31.48
30.90
31.13
30.72
31.49
30.76
30.72
30.65
31.24
30.59
30.60
30.67
LogLx,abs
33.31
34.83
31.57
33.10
31.89
33.24
31.71
31.67
34.08
32.99
39.76
31.04
31.72
31.32
34.09
32.04
33.81
30.83
31.44
31.64
31.41
31.07
30.89
31.53
32.69
32.11
31.65
33.31
34.07
32.88
33.87
31.63
35.18
31.23
33.93
32.30
30.77
32.62
34.38
31.25
30.75
32.57
34.57
LogLx,unabs
Luminositiesc
Table 11
Quantile spectral interpolations and luminosity estimates for all ChIcAGO sources within
HII regions that have > 5 X-ray counts
1.35
3.25
2.40
1.62
2MASS N(< Ks )
1.38
1.06
5.29
3.02
2.21
1.88
3.15
1.71
GLIMPSE N(< M3.6 )
False associations (×10−2 )d
T HE C H I C AGO S URVEY
47
NH
Fx,abs
Fx,unabs
(kpc)
Ref
Distanceb
LogLx,abs
LogLx,unabs
Luminositiesc
2MASS N(< Ks )
GLIMPSE N(< M3.6 )
False associations (×10−2 )d
The quantile analysis interpolated absorbed Mekal model parameters including the temperature, kT , and absorption column density NH (1022 cm−2 ), as well as the absorbed and unabsorbed X-ray fluxes, Fx,abs and Fx,unabs (10−14 erg cm−2
References. — 1: Busfield et al. (2006); 2: Russeil (2003); 3: McClure-Griffiths et al. (2001); 4: Fich & Blitz (1984)
kT
Absorbed Mekal interpolationa
sources where the chance of random alignment with a survey source is > 0.01.
s−1 ), respectively, in the 0.3 − 8.0 keV energy range. (If kT = 82.45 then this indicates that the spectral interpolation of this ChIcAGO source has hit the hard limit for this parameter.)
b
The distances used to estimate the absorbed and unabsorbed luminosities. The corresponding reference is also listed.
c
The Log of the absorbed and unabsorbed luminosities, Lx,abs and Lx,unabs (erg s−s ), respectively, in the 0.3 − 8.0 keV energy range.
d
Chance of finding a 2MASS (or GLIMPSE) source with a Ks (or 3.6µm) magnitude brighter than the counterpart listed in Tables 2 or 7, within the ChIcAGO source’s 95% position error circle. This value is only quoted for the ChIcAGO
a
ChI
ChIcAGO Source
Table 11 — Continued
48
T HE C H I C AGO S URVEY
49
Table 12
Confirmed and tentative identifications of the AGPS sources, including both literature and
ChIcAGO survey identifications
AGPS ID
AX J143148–6021
AX J143416–6024
AX J144042–6001
AX J144519–5949
AX J144547–5931
AX J144701–5919
AX J145605–5913
AX J145732–5901
AX J150436–5824
AX J151005–5824
AX J153751–5556
AX J153818–5541
AX J153947–5532
AX J154122–5522
AX J154233–5519
AX J154557–5443
AX J154905–5420
AX J154951–5416
AX J155035–5408
AX J155052–5418
AX J155331–5347
AX J155644–5325
AX J155831–5334
AX J161929–4945
AX J162011–5002
AX J162046–4942
AX J162125–4933
AX J162138–4934
AX J162155–4939
AX J162208–5005
AX J162246–4946
AX J163159–4752
AX J163252–4746
AX J163351–4807
AX J163524–4728
AX J163555–4719
AX J163751–4656
AX J163904–4642
AX J164042–4632
AX J165105–4403
AX J165217–4414
AX J165420–4337
AX J165437–4333
AX J165646–4239
AX J165707–4255
AX J165723–4321
AX J165901–4208
AX J165904–4242
AX J165922–4234
AX J165951–4209
AX J170006–4157
AX J170017–4220
AX J170047–4139
AX J170052–4210
AX J170112–4212
AX J170349–4142
AX J170444–4109
AX J170506–4113
AX J170536–4038
AX J170555–4104
AX J171715–3718
AX J171804–3726
AX J171910–3652
AX J171922–3703
AX J172050–3710
AX J172105–3726
AX J172550–3533
ChIcAGO IDa
ChI J143148–6021_3
ChI J144042-6001_1
ChI J144519-5949_2(1,3-6)
ChI J144547-5931_1
ChI J144701-5919_1
ChI J150436–5824_1
ChI J151005–5824_(1-11)
ChI J153818-5541_1
ChI J154122–5522_1
ChI J154557–5443_1
ChI J154557–5443_2
ChI J154557–5443_3
ChI J154905–5420_(1-11)
ChI J155035–5408_1
ChI J155035–5408_3
ChI J155331–5347_1
ChI J155831–5334_1
ChI J162011-5002_1
ChI J162046–4942_1
ChI J162208–5005_(1-3)
ChI J163252-4746_2
ChI J163751–4656_1
ChI J165105–4403_1
ChI J165217–4414_1
ChI J165420–4337_1
ChI J165646–4239_1
ChI J165646–4239_2
ChI J165707–4255_1
ChI J170017-4220_1
ChI J170052–4210_1
ChI J170444–4109_1
ChI J170444–4109_2
ChI J170536–4038_1
ChI J171910–3652_2
ChI J171922–3703_1
ChI J172050-3710_1
ChI J172550–3533_1
ChI J172550–3533_2
ChI J172550–3533_3
Typeb
U
RS CVn
PMS
WR and H II
OIf+
WR
U
U
U
H II
U
LMXB
U
ASC/PMS
U
U
U
U
H II
U
ASC/PMS
MS/ASC
Magnetar
ASC/PMS
KOIIIe
U
HMXB
CV
MS/ASC
U
U
K3III
H II
Magnetar
HMXB
CWB
Of?p
U
SNR/PWN
U
SyXB
PWN
U
U
U
Binary Star
ASC/PMS
U
ASC/PMS
U
U
Be star
U
ND
CV
HMXB
HMXB
ASC/PMS
U
SNR
ASC/PMS
U
U
ASC/PMS
U
U
SNR
ASC/PMS
U
ASC
SNR
AGN or HMXB
CV
ASC/PMS
IDc
HD 127535
HD 128696
GAL 316.8–00.1
G320.3–0.3
Referenced
Flage
1
2,3*
2*
1
4,4
4,4
n,R,n
n,n,n
n,n,n
T,T,N
I,I,n
I,I,n
n,n,n
F,n,n
n,n,n
I,n,N
F,n,n
n,n,N
n,n,n
T,T,N
n,n,n
n,n,n
n,n,n
n,n,n
I,n,N
F,n,n
n,T,N
n,T,N
n,n,n
T,T,N
n,n,n
n,R,n
n,n,n
n,n,N
T,T,N
n,n,n
n,n,n
n,n,n
I,n,N
I,n,n
n,n,n
I,I,n
n,n,n
F,n,n
n,n,n
n,R,n
n,n,n
n,n,n
n,n,n
n,R,n
n,R,n
n,n,n
n,T,N
n,R,n
T,T,N
n,n,n
F,n,n
n,n,n
n,n,n
F,n,n,
n,n,n
T,T,N
n,n,n
T,T,N
F,n,n
n,n,n
n,T,N
n,n,n
n,n,n
T,T,N
F,n,n
F,n,n
n,n,n
T,T,N
n,n,n
T,T,N
n,n,n
n,T,N
n,I,n
n,T,N
1
1
5
1
G326.96+0.03
1E 1547.0–5408
TYC 8697–1438-1
IGR J16195–4945
HD 147070
G333.6–0.2
PSR J1622–4950
IGR J16320–4751
HD 148937
SNR G337.2+0.1
IGR J16393-4643
SNR G338.3–0.0
HD 152335
V921 Sco
AX J1700.1–4157
OAO 1657–415
SNR G344.7–0.1
1
1
1
1
1
1
6,7
1
8
1**
9,3**
5
1**
2*
1
10,10
11,12
4,4
13,3*
14
1
15,15
16*
1
1
1**
2,3*
1
1
1
**
17,3
18,18
19
20,20*
1
21*
1
1
1
SNR G349.7+0.2
SNR G350.1–0.3
V478 Sco
22*
1
1
5
23
1
1
1
50
Table 12 — Continued
AGPS ID
AX J172623–3516
AX J172642–3504
AX J172642–3540
AX J172743–3506
AX J173441–3234
AX J173518–3237
AX J173548–3207
AX J173628–3141
AX J175331–2538
AX J175404–2553
AX J180225–2300
AX J180800–1956
AX J180816–2021
AX J180838–2024
AX J180857–2004
AX J180902–1948
AX J180948–1918
AX J180951–1943
AX J181033–1917
AX J181116–1828
AX J181120–1913
AX J181211–1835
AX J181213–1842
AX J181705–1607
AX J181848–1527
AX J181852–1559
AX J181915–1601
AX J181917–1548
AX J182104–1420
AX J182216–1425
AX J182435–1311
AX J182442–1253
AX J182509–1253
AX J182530–1144
AX J182538–1214
AX J182651–1206
AX J182846–1116
AX J183039–1002
AX J183114–0943
AX J183116–1008
AX J183206–0938
AX J183206–0940
AX J183221–0840
AX J183231–0916
AX J183345–0828
AX J183356–0822
AX J183440–0801
AX J183506–0806
AX J183518–0754
AX J183528–0737
AX J183607–0756
AX J183618–0647
AX J183800–0655
AX J183931–0544
AX J183957–0546
AX J184004–0552
AX J184008–0543
AX J184024–0544
AX J184121–0455
AX J184355–0351
AX J184400–0355
AX J184447–0305
AX J184600–0231
AX J184610–0239
AX J184629–0258
AX J184652–0240
AX J184738–0156
AX J184741–0219
AX J184848–0129
AX J184930–0055
AX J185015–0025
ChIcAGO IDa
ChI J172623–3516_1
ChI J172642–3504_1
ChI J172642-3540_1
ChI J173548–3207_1
ChI J175404–2553_3
ChI J180857–2004_1
ChI J180857–2004_2
ChI J181116–1828_2
ChI J181213–1842_7
ChI J181213–1842_9
ChI J181852–1559_2
ChI J181915-1601_2
ChI J181915-1601_3
ChI J182435–1311_1
ChI J182509–1253_1
ChI J182509–1253_3
ChI J182530–1144_2
ChI J182538–1214_1
ChI J182651–1206_4
ChI J183116-1008_1
ChI J183206-0938_1
ChI J183345–0828_1
ChI J183356–0822_2
ChI J183356–0822_3
ChI J184652–0240_1
ChI J184738–0156_1
ChI J184741–0219_3
Typeb
ASC/PMS
U
K2V
SNR
CWB
SNR
U
U
ND
U
OB and PMS stars
U
ND
Magnetar
U
WR
SNR
PWN
Magnetar
U
U
U
SNR
U
ASC/PMS
U
U
Magnetar
WR
U
U
SNR/PWN
U
MS-O
U
ASC/PMS
U
U
ASC/PMS
MS-O
U
AGN
U
CWB
CWB
U
CV
U
PWN
WR
U
MS-O
U
U
U
SyXB
ND
U
PSR/PWN
LBV
U
U
U
U
Magnetar/SNR
SNR
U
U
U
U
SNR/PWN
MS-O
CWB
AGN
Globular cluster
SNR
SNR
IDc
CD-35 11565
SNR G352.7–0.1
HD 159176
SNR G355.6–0.0
Triffid Nebula (HD 164492)
SGR 1806–20
SNR 10.5–0.0
PSR J1809–1917
XTE J1810–197
SNR G12.0–0.1
Referenced
Flage
1**
1
1
24*
25,3*
26*
1
T,T,N
n,n,n
I,I,n
n,n,n
n,n,n
n,n,n
n,n,n
F,n,n
F,n,n
n,n,n
n,n,n
n,n,n
F,n,n
n,n,n
n,n,n
n,T,N
I,n,n
n,n,n
n,n,n
F,n,n
n,R,n
F,n,n
n,n,n
n,R,n
n,T,N
F,n,n
n,n,n
n,n,N
n,T,n
n,n,n
F,n,n
n,n,n
F,n,n
T,T,N
n,n,n
T,T,N
n,n,n
n,n,n
T,T,N
T,T,N
n,n,n
n,n,n
n,n,n
n,n,n
n,n,N
n,n,n
n,n,n
n,n,n
n,n,N
n,T,N
n,n,n
n,T,N
n,n,n
n,n,n
F,n,n
n,n,n
F,n,n
n,n,n
n,n,n
n,n,n
n,n,n
n,n,n
F,n,n
n,n,n
n,n,n
n,n,n
F,n,n
F,n,n
n,n,n
n,n,n
n,n,n
T,T,N
I,I,n
I,I,N
n,n,n
n,n,n
n,n,n
1
27
28,29**
1
1
30
31**
32,33
1
**
26*
1
1
34
1**
1
SNR G16.7+0.1
35*
1
1
1
1
1
1
36,1
37,37
37,37
AX J1832.3–0840
18,18
PSR B1830–08
38*
1
1
1
Scutum X-1
39,39
PSR J1838–0655
G26.47+0.02
40
41,41
**
1E 1841–045/SNR G27.4+0.0 (Kes 73)
SNR G28.6–0.1
42*
43
SNR G29.7-0.3(Kes 75)/PSR J1846–0258
44*
1
4,4
1
45
46*
47
WR121a
GLIMPSE–C01
SNR G31.9+0.0 (3C 391)
SNR G32.4+0.1
T HE C H I C AGO S URVEY
51
Table 12 — Continued
AGPS ID
AX J185240+0038
AX J185551+0129
AX J185608+0218
AX J185643+0220
AX J185651+0245
AX J185721+0247
AX J185750+0240
AX J185905+0333
AX J190007+0427
AX J190144+0459
AX J190534+0659
AX J190734+0709
AX J190749+0803
AX J190814+0832
AX J190818+0745
AX J191046+0917
AX J191105+0906
AX J194152+2251
AX J194310+2318
AX J194332+2323
AX J194622+2436
AX J194649+2512
AX J194939+2631
AX J194951+2534
AX J195006+2628
ChIcAGO IDa
ChI J185608+0218_1
ChI J185643+0220_2
ChI J185750+0240_1
ChI J190534+0659_1
ChI J190749+0803_1
ChI J190814+0832_2
ChI J190818+0745_1
ChI J194152+2251_2
ChI J194310+2318_5(1-4,6-10)
ChI J194332+2323_(1-8)
ChI J194939+2631_1
ChI J195006+2628_(1-5)
Typeb
IDc
Referenced
Flage
SNR/PSR
SNR/PWN
ASC/PMS
U
U
U
U
Galaxy cluster
U
U
MS/ASC
SNR
U
MS/ASC
U
HMXB
SNR
U
O7V((f)) and H II
H II
U
Hα Star
CV
U
H II
SNR G33.6+0.1 (Kes 79)/PSR J1852+0040
SNR G34.7–0.4 (W44)/PSR B1853+0.1
48*
49
1**
1
n,n,n
n,n,n
T,T,N
n,n,n
n,n,n
n,n,n
n,R,n
n,n,n
n,n,n
n,n,n
T,T,N
n,n,n
n,R,n
T,T,N
n,R,n
n,n,N
n,n,n
n,R,n
I,I,N
I,n,N
F,n,n
n,n,n
n,n,N
F,n,n
I,n,N
AX J185905+0333
SNR G41.1–0.3 (3C 397)
AX J1910.7+0917
SNR G43.3–0.2 (W49B)
G59.5–0.2
G59.5–0.2
1
50
1
51*
1
1
1
52
53*
1
1*
1*
EM* VES 52
54*
55
G62.9+0.1
1
References. — 1: This paper; 2: Sugizaki et al. (2001); 3: Skrutskie et al. (2006); 4: Anderson et al. (2011); 5: Degenaar et al. (2012); 6: Bernardini et al. (2011); 7: Israel et al.
(2009); 8: Torres et al. (2006); 9: Tomsick et al. (2006); 10: Anderson et al. (2012); 11: Rodriguez et al. (2006); 12: Walter et al. (2006); 13:Nazé et al. (2008); 14: Combi et al.
(2006); 15: Bodaghee et al. (2006); 16: Funk et al. (2007); 17: Hamaguchi et al. (2005); 18: Kaur et al. (2010); 19: Markwardt et al. (2010); 20: Chakrabarty et al. (2002); 21: Combi
et al. (2010); 22: Lazendic et al. (2005); 23: Gaensler et al. (2008); 24: Giacani et al. (2009); 25: De Becker et al. (2004); 26: Yamauchi et al. (2008); 27: Rho et al. (2004); 28:
Mereghetti et al. (2005); 29: Israel et al. (2005); 30: Brogan et al. (2006); 31: Kargaltsev & Pavlov (2007); 32: Gotthelf & Halpern (2007); 33: Israel et al. (2004); 34: Mereghetti
et al. (2012); 35: Helfand et al. (2003a); 36: Bassani et al. (2009); 37: Motch et al. (2010); 38: Kargaltsev et al. (2012); 39: Kaplan et al. (2007); 40: Gotthelf & Halpern (2008);
41:(Paron et al. 2012); 42: Morii et al. (2003); 43: Bamba et al. (2001); 44: Helfand et al. (2003b); 45: Pooley et al. (2007); 46: Chen et al. (2004); 47: Yamaguchi et al. (2004);
48: Gotthelf & Halpern (2005); 49: Petre et al. (2002); 50: Yamauchi et al. (2011); 51: Safi-Harb et al. (2005); 52: Pavan et al. (2011); 53: Hwang et al. (2000); 54: Kohoutek &
Wehmeyer (1997); 55: Zolotukhin & Chilingarian (2011)
a
The equivalent ChIcAGO name of the AGPS source. All ChIcAGO sources with > 20 X-ray counts are listed. In a few cases there is more than one ChIcAGO source listed for a
given AGPS source. For a given identified H II region, all of the ChIcAGO sources contributed to the X-ray emission originally detected with ASCA in the AGPS. In these cases the
ChIcAGO source name suffixes are listed in parentheses. If a suffix is listed before the parentheses then this ChIcAGO source corresponds to an X-ray source whose stellar type is
listed in column three, before the H II classification.
b
The source type abbreviations are ASC: active stellar corona, AGN: active galactic nucleus, CV: cataclysmic variable, CWB: colliding-wind binary, H II: young and massive stars
in the H II region named in the “ID” column; HMXB: high-mass X-ray binary, LBV: luminous blue variable, LMXB: low-mass X-ray binary, Magnetar: magnetar, MS: massive
star, MS-O: massive O-type star, ND: no ChIcAGO sources detected in the Chandra observation (no detection), PMS: pre-main sequence star, PSR: X-ray emission from a rotationpowered pulsar, PWN: pulsar wind nebula, SNR: supernova remnant, SyXB: symbiotic X-ray binary, U: unknown, and WR: Wolf-Rayet star. The other abbreviations are the spectral
type of the stellar counterpart.
c
The most commonly used name
d
The * and ** symbols indicate those AGPS sources that were correctly and incorrectly identified by Sugizaki et al. (2001), respectively. Those archival AGPS sources and identified
ChIcAGO sources used in the statistical analysis in Section 4.2 have two references in this Table, the first being the paper describing an X-ray fit from which we derived an absorbed
X-ray flux, and the second being the paper from which the NIR counterpart (J, H, and Ks magnitudes) information was obtained. All the longer-wavelength IR counterpart information
(3.6, 4.5, 5.8, and 8.0 µm magnitudes) was gathered from the GLIMPSE catalogs and archives.
e
Flags that correspond to the identification properties of the AGPS and ChIcAGO sources. One flag is listed for each of the first three columns. I: Identified sources through work in
the ChIcAGO survey, T: Tentatively identified sources using the X-ray and infrared population statistics in Section 4.2, F: AGPS sources for which only ChIcAGO sources with ≤ 20
X-ray counts were detected. These include AGPS sources where no sources were detected in the corresponding ChIcAGO Chandra observations but excludes those AGPS sources
that have been identified as H II regions, R: Figure 8 Region iv sources; N: Unconfirmed classification type; n: no flag.
52
Table 13
Chandra point sources with > 20 X-ray counts detected between 30 − 50 from the AGPS
position
AGPS Sourcea
d
Net Countsd
Dec
(J2000)
Error
(00 )
from ASCA
(0 )
0.3-8
(keV)
J150436–5824
J154557–5443
15:04:13.54
15:46:09.08
15:45:54.60
15:49:12.40
15:49:14.67
15:50:19.25
15:50:05.97
17:04:26.88
17:26:27.79
18:12:29.26
18:19:29.65
18:47:52.81
18:47:32.53
19:43:29.97
-58:25:07.4
-54:39:12.9
-54:38:49.6
-54:16:30.2
-54:24:54.6
-54:11:27.3
-54:07:23.1
-41:07:34.9
-35:07:27.2
-18:45:21.6
-16:04:33.3
-01:59:57.9
-02:22:23.8
+23:20:52.3
0.84
0.89
0.94
0.94
1.03
0.89
1.07
0.95
0.88
1.02
0.95
0.89
0.93
0.88
3.0
4.2
4.3
4.1
4.6
3.6
4.5
3.9
4.5
4.7
4.6
4.8
4.0
3.1
47.7 ± 8.0
48.0 ± 8.1
38.9 ± 7.4
31.8 ± 6.8
20.2 ± 5.7
35.5 ± 7.1
22.8 ± 6.0
26.7 ± 6.3
72.1 ± 9.6
21.9 ± 5.8
30.0 ± 6.5
96.5 ± 10.9
34.2 ± 7.0
28.4 ± 6.5
J170444–4109
J172642–3504
J181213–1842
J181915–1601
J184738–0156
J184741–0219
J194332+2323
c
Offsetc
RA
(J2000)
J155035–5408
b
Positionb
AX
J154905–5420
a
wavdetect Position
Predicted Countse
Total Countsf
< 30
139
147
154
96
178
84
152
242
95
206
92
201
150
211
143
170
120
172
132
120
53
64
2MASS Name
2MASS J
15460913–5439128
15491237–5416301
15491463–5424549
15501925–5411271
17042687–4107351
17262781–3507281
18122923–1845222
18475281–0159575
19432997+2320524
The AGPS source for which one or two X-ray point sources with > 20 counts were detected in the corresponding ChIcAGO Chandra observation between 30 − 50 .
The total 95% position error circle (in arcseconds) of the Chandra point source taking into account the wavdetect position error and the absolute astrometric accuracy of Chandra.
The offset, in arcminutes, between the AGPS position published in Sugizaki et al. (2001) and the wavdetect position of the Chandra point source.
The net number of counts in the 0.3 − 8.0 energy range. The source counts were calculated using a source region with a radius equal to 95% of the PSF at 1.5 keV. The total counts
have been background subtracted and the error corresponds to the upper 1σ confidence limit calculated using Gehrels (1986) statistics.
e
The number of X-ray counts that Chandra PIMMS predicts should be detected in the ChIcAGO Chandra observation based on the power law spectral fits measured by Sugizaki
et al. (2001).
f
The total number of X-ray counts (rounded to the nearest count) from all the sources detected in the ChIcAGO Chandra observations within 30 of the AGPS position.