Tracing cosmic accretion
through the
XMM-Newton Medium Survey
(XMS)
Xavier Barcons
On behalf of the AXIS/XMS/SSC team
Index
 The role of medium sensitivity surveys
 The XMS survey
 The content of the XMS survey
 Tips for statistical identifications
 Outlook and future work
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The role of Medium Surveys
 Bridge between most popular deep surveys and
surveys of the local Universe
 The average XMM-Newton observation (10-20 ks
of GTI) is a Medium Sensitivity Survey:
* The 2XMM catalogue will be a huge MSS
 The bulk of the cosmic X-ray background resides
at intermediate X-ray fluxes (~10-14 erg cm-2 s-1)
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Relative contribution to XRB per
flux decade
Fractional contribution to XRB
7,0E-12
 S dN(S)/d log S
6,0E-12
5,0E-12
0.5-2 keV
0.5-4.5 keV
2-10 keV
4,0E-12
3,0E-12
2,0E-12
1,0E-12
0,0E+00
1,0E-16
1,0E-15
1,0E-14
X-ray flux (cgs)
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1,0E-13
1,0E-12
Fraction of XRB resolved by
X-ray surveys
1
0,9
XMS
Fraction of XRB
0,8
0,7
The XMS resolves
~50% of the
0.5-4.5 keV
X-ray background
0,6
0,5
BSS
0,4
0,3
Deep
0,2
0,1
0
1,0E-16
1,0E-15
1,0E-14
X-ray flux (cgs)
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1,0E-13
1,0E-12
The XMS survey and its optical
identification
Definition of the XMS sample
 25 XMM-Newton target fields:
* Galactic latitude |b|>20 deg
* X-ray observations with EPIC-pn
detector in FULL-FRAME-MODE
* ~Avoided fields with bright and/or
extended targets
* Good time intervals > 10 ksec
* Available early on in the mission
 Using SAS v6.1.1 to produce final source list
and products:
* Exposure and background maps
* Source detection
* Spectra and calibration matrices
 Areas around target + OOT+ near the pn
CCD gaps excluded
 Own empirical sentitivity maps from
detected source parameters
 284 sources with 0.5-4.5 keV flux
>2 10-14 erg cm-2 s-1
 Very detailed source screening
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Mrk 205
NGC4291
Statistics of XMS fields
Field
GTI #
UZ Lib
23
7
A1837
45
9



Mkn205
17
18



A399
14
11



Mkn3
23
13



B21028
23
11



MS0737
20
11



B21128
14
15



MS1229
28
9



Cl0016
29
14



PB5062
28
6



Cl0939
44
7



PHL5200 43
18



Eq Peg
12
14



PKS2126
16
9



G133_2
18
11



PKS2135
28
13



G133_1
20
8



S50836
25
11



HD11755 33
16



SDS1
43
13



IRAS224 20
12



SDS2
41
9



LBQS221 90
13



SDS3
14
6



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
Optical identification of XMS
 Optical imaging: g’,r’,i’ and more to r’~23-24mag
 Reliable & unique candidate counterpart in r’/i’ for
virtually all sources (< 5” or < 5)
 Optical spectroscopy
* 50% from AXIS programme (WHT, TNG, NOT):
multi-fibre and long-slit spectroscopy
* 20% from Calar Alto/3.5m long-slit spectroscopy
* 15% from VLT/FORS2 long-slit spectroscopy
* A few from AAT/2dF, SUBARU/FOCAS, and others
 Preliminary results from 2 XMM-Newton fields
(~30 sources) in Barcons et al (2002)
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XMS Identification status
Sources
X-ray




25 XMM fields
XID:0.5-4.5 keV
SXID>210-14cgs
Ω=3.3 deg2
Identified
Unid R<20
Unid 20<R<21
Unid 21<R<22
Unid R>22
Empty
Need imaging
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Number
%
284
242
6
6
4
24
2
1
100
85
2.5
2.5
1.5
8
1
0
The content of the XMS
Identification breakdown
Remaining incompleteness & biases
Towards the X-ray luminosity function
Breakdown of identified sources in
the XMS
Class
Broad-Line
AGN
Narrow Line
Galaxies
Absorption
Line Galaxies
Stars
BL Lac
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Number
%
178
74
37
15
8
4
18
1
7
0
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Fluxes and redshifts
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Incompleteness and remaining biases
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Redshift distribution
30
25
Number
20
ALG
NELG
BLAGN
15
10
5
0
0
0,2 0,4 0,6 0,8
1
1,2 1,4 1,6 1,8
2
z
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2,2 2,4 2,6 2,8
QSO-2s
S(0.5-4.5)=1.1 10-13 erg cm-2 s-1
z=0.711
LX=1044.4 erg s-1
Absorbed:
=0.55
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The L-z plane and the X-ray
Luminosity Function
Unfortunately,
photo-z’s do not
work with our
limited colour
information
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Source counts
Γd=1.34+0.01-0.07
Γu=2.55+0.03-0.04
Sb=1.69+0.02-0.0110-14 cgs
See poster G.2 for more details
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X-ray spectral properties of AGN
 Spectra of individual
sources well matched to
unified model, but with
exceptions (Mateos et al
2005)
 X-ray spectral templates:
de-redshifted average
spectra (see poster E.11 by
Corral et al)
?
?
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Tips on statistical identification
Statistical identification
 Probabilistic classification of X-ray sources, based
on:
*
*
*
*
X-ray colours
Optical colours
X-ray to optical flux ratios
X-ray and/or optical morphology
 Large parameter space: start with “preliminary
inspection” (fishing expedition), later apply
mathematical tools (PCA, ANNs, etc.)
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>85% BLAGN
>50% NELG
>60% NELG
>80% NELG
100% NELG
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HR2=(H-S)/(H+S)
H=2.0-4.5 keV
S=0.5-2.0 keV
Optical colour-colour diagrams
2,5
50% NELGs
SDSS
50% “red” BLAGNs
Early-type galaxies
2
SDSS
QSOs
1,5
BLAGN
NELG
Gal
Star
Noid
r'-i'
1
0,5
0
95% BLAGNs
-0,5
-1
-1
-0,5
0
1
0,5
g'-r'
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1,5
2
2,5
Optical vs X-ray colours
Red & Hard
NELGs
Red2,5 & Soft
ALG2
g'-r'
1,5
BLAGN
NELG
Gal
Star
Noid
1
0,5
Blue
BLAGN
0
-0,5
-1
-1,2
-1
-0,8
-0,6
-0,4
-0,2
HR2
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0
0,2
0,4
Obscuration/reddening
2
1,5
log (fX/fopt)
1
BLAGN
NELG
Gal
Star
Noid
0,5
0
-0,5
-1
-1,5
-2
-1
-0,5
0
0,5
1
g'-r'
r'-i'
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1,5
2
2,5
Obscuration/reddening
2
1,5
log (fX/fopt)
1
BLAGN
NELG
Gal
Star
Noid
0,5
0
-0,5
-1
-1,5
-2
-1
-0,5
0
0,5
1
r'-i'
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1,5
2
2,5
Tips for statistical identifications
 Sources with log (fX/fopt)<-1.5 are invariably stars
 Optically blue objects are 95% BLAGN
 Optically red objects include both broad-line and
narrow line AGN
 Red & soft galaxies do not have emission lines
 Red & hard galaxies have narrow emission lines
 There is a large patch of parameter space shared
by both broad and narrow line AGN.
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Outlook and future work
 Spectroscopic identification of remaining 15%
objects needed (photo-z’s do not work)
 Combine with Bright and Deep Surveys to compute
AGN X-ray luminosity function and evolution
 Compute Accretion power as a function of z, both
for absorbed and unabsorbed sources
 Explore larger sample (XMM/2dF) in the search
for statistical identification handles
 Apply statistical identification to 2XMM catalogue
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Thanks to:
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Francisco Carrera
Maite Ceballos
Silvia Mateos
Amalia Corral
Francesca Panessa
Jacobo Ebrero
Mat Page
Axel Schwope
Mike Watson
Roberto Della Ceca
Jonathan Tedds
Tommaso Maccacaro
And many more…
The X-ray Universe 2005