An X-ray Study of the Bright Supernova Remnant G296.1-0.5

with XMM-Newton

SNRs and PWNe in the Chandra EraBoston, MA – July 8th, 2009

Daniel Castro, CfA-USBCollaborator: Pat Slane, CfA

Outline

• Introduction- 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

IntroductionRadio Observations (Molonglo Cross)

• 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

• 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

MOST, 0.843 GHz (Whiteoak & Green, 1996)

ROSAT (Hwang & Markert, 1994)

• 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

PSPC spectrum of G296.1-0.5, single temperature ionized plasma fit

ROSAT PSPC data revisited

• Low column density nH = 8 (±1) x 1020 cm-2

• Single temperature (~0.5 keV) ionized plasma (solar abundances)

ASCA Observations

GIS Spectrum:• Low column density

(>6x1020 cm-2)• Single temperature

ionized plasma (~ 0.5 keV)• Mg and Si lines are

present

GIS spectrum of G296.1-0.5, single temperature ionized plasma fit

ASCA GIS image with PSPC contours

Morphology of G296.1-0.5CO Emission Map• Integrated CO emission suggest higher densities towards darker areas• No velocity slice provides sufficient information to determine the location of dense material

regions in relation to the object

ROSAT PSPC image with contours of line-of-sight CO emission XMM EPIC RGB image of CTB 109 (Sasaki et al., 2004)

• No apparent excess absorption towards the SE, in X-rays

• Shock interaction with cloud of dense material in this direction could explain apparent half-shell morphology (like it has been suggested for CTB 109, Sasaki et al., 2004)

XMM Observations

XMM image of G296.1-0.5, with pointing regions in white

• 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

• 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 ObservationsMosaic RGB image of EPIC MOS2 data

R: 0.3 – 0.7 keVG: 0.7 – 1.0 keVB: 1.0 – 3.0 keV

• 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 Spectral Study

Mosaic image of EPIC data, with extraction regions

Spectra from region A from EPIC MOS1 (black) and MOS2 (red)

• 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)

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

Mosaic image of EPIC data, with extraction regions

Spectra from region A from EPIC MOS1 (black) and MOS2 (red)

Assuming Sedov expansion:• Swept-up Mass ~ 2 (d1kpc

5/2) M

• Density ~ 0.2 (d1kpc -1/2)cm-3

• Age ~ 4000 d1kpc yr

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

Mosaic image of EPIC data, with extraction regions

• 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

Relative Abundances for region A

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

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