An X-ray Study of the Bright
Supernova Remnant G296.1-0.5 with
XMM-Newton
SNRs and PWNe in the Chandra Era
Boston, MA – July 8th, 2009
Daniel Castro, CfA-USB
Collaborator: Pat Slane, CfA
Outline
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Introduction
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Radio and other observations
X-ray study with ROSAT
ASCA Observations
Morphology of G296.1-0.5
XMM Observations
XMM Spectral Study
Abundances in G296.1-0.5
Summary
Introduction
MOST, 0.843 GHz (Whiteoak & Green, 1996)
Radio Observations (Molonglo Cross)
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Clark et al., 1975
Caswell & Barnes, 1983
Bright SW limb
33’ mean angular size
Distance estimate from mean Σ-D
relation = 7.7 kpc
Possibly two different SNRs
Other observations
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Very bright in the X-ray range (Einstein
IPC count rate = 3.2 cnts s-1)
Optical observations (Longmore et al.,
1977) reveal faint filaments and
nebulosity in Hα and [SII].
- Distance estimate ~ 4 kpc
ROSAT (Hwang & Markert, 1994)
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3 bright regions (little spectral
variation)
nH ~ 2 x1021cm-2
Single temperature (~0.2 keV)
underabundant plasma (3%
solar)
Two thermal components (~0.1
and 0.35 keV) with solar
abundances
Left: MOST image with PSPC contours. Right: PSPC image
ROSAT PSPC data revisited
PSPC spectrum of G296.1-0.5, single temperature ionized plasma fit
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Low column density
nH = 8 (±1) x 1020 cm-2
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Single temperature (~0.5 keV)
ionized plasma (solar abundances)
ASCA Observations
ASCA GIS image with PSPC contours
GIS spectrum of G296.1-0.5, single temperature ionized plasma fit
GIS Spectrum:
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Low column density
(>6x1020 cm-2)
Single temperature
ionized plasma (~ 0.5 keV)
Mg and Si lines are
present
Morphology of G296.1-0.5
CO Emission Map
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Integrated CO emission suggest higher densities towards darker areas
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No velocity slice provides sufficient information to determine the location of dense material
regions in relation to the object
• No apparent excess absorption towards the SE,
in X-rays
• Shock interaction with cloud of dense material
in this direction could explain apparent halfshell morphology (like it has been suggested
for CTB 109, Sasaki et al., 2004)
ROSAT PSPC image with contours of line-of-sight CO emission
XMM EPIC RGB image of CTB 109 (Sasaki et al., 2004)
XMM Observations
XMM image of G296.1-0.5, with pointing regions in white
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G296.1-0.5 was observed with three
pointings of XMM-Newton
Exposure times (after removing flare and
high background periods):
• P1 ~ 12 ks
• P2 ~ 10 ks
• P3 ~ 8 ks
Consistent with other X-ray observations
Brightest region located in the northern
limb
XMM Observations
Mosaic RGB image of EPIC MOS2 data
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G296.1-0.5 was observed with three
pointings of XMM-Newton
Exposure times (after removing flare and
high background periods):
• P1 ~ 12 ks
• P2 ~ 10 ks
• P3 ~ 8 ks
Consistent with other X-ray observations
Brightest region located in the northern
limb
R: 0.3 – 0.7 keV
G: 0.7 – 1.0 keV
B: 1.0 – 3.0 keV
XMM Spectral Study
• Preliminary spectral analysis shows an
emission profile well described by a single
temperature ionized plasma, in all regions of
the SNR
• The spectral fits favor low absorption (nH < 8 x
1020 cm-2)
Spectra from region A from EPIC MOS1 (black) and MOS2 (red)
Mosaic image of EPIC data, with extraction regions
nH = 3.0 +0.7-1.9 x 1020 cm-2
kTA = 0.52+0.04-0.04 keV
net = 7.7+2.6-1.2 x 1010 s.cm-3
XMM Spectral Study
Assuming Sedov expansion:
• Swept-up Mass ~ 2 (d1kpc 5/2) M
• Density ~ 0.2 (d1kpc -1/2)cm-3
• Age ~ 4000 d1kpc yr
Spectra from region A from EPIC MOS1 (black) and MOS2 (red)
Mosaic image of EPIC data, with extraction regions
nH = 3.0 +0.7-1.9 x 1020 cm-2
kTA = 0.52+0.04-0.04 keV
net = 7.7+2.6-1.2 x 1010 s.cm-3
Abundances in G296.1-0.5
• Apparent enhanced abundance of some metals (N,
Ne and Mg)
• Possible underabundance of Oxygen
• The spectral fit, in most regions of the the SNR, is
significantly improved with an overabundance of
Nitrogen
• The circumstellar winds of Wolf-Rayet and LBV stars
are known to be enriched in N, and O deficient
Mosaic image of EPIC data, with extraction regions
N
O
Ne
Mg
2.99-0.54+0.71
0.79-0.08+0.10
1.64-0.22+0.20
1.43-0.27+0.29
Relative Abundances for region A
Summary
• G296.1-0.5 is a bright, nearby supernova
remnant
• Spectral characteristics show little variation
from region to region of the object, suggesting
this is a single remnant
• Apparent enhanced abundance of some metals
(N, Ne and Mg), together with underabundance
of Oxygen. Possibly explained by interaction of
the shock with the circumstellar wind from WR or
LBV progenitor star