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<strong>The</strong> <strong>environment</strong> <strong>near</strong> <strong>SNR</strong><br />
<strong>W41</strong> <strong>and</strong> <strong>W30</strong><br />
Li Hui<br />
Department of Astronomy,<br />
Nanjing University
Outline<br />
•Observational information<br />
•Prominent features <strong>and</strong> similarity.<br />
•Possible explanations
<strong>W41</strong>
Detailed Ch<strong>and</strong>ra source<br />
XMM x-ray nebula<br />
G8.31-0.09<br />
Fermi source<br />
HESS obs<br />
Radio continuum
XMM-Newton observation<br />
0.3-1.5keV<br />
1.5-7keV<br />
Non-thermal<br />
Highly absorbed hard X-rays<br />
Tian et al 2007
New analysis<br />
•PWN powered by unknown pulsar??<br />
Mukherjee et al. 2009
Ch<strong>and</strong>ra map<br />
Zoom in<br />
Misanovic et al 2011
CO observation<br />
M~10^6 M_sun<br />
13CO 61-66km/s<br />
12CO/13CO 70-85km/s Albert et al 2006; Tian et al 2007
SED of <strong>W41</strong><br />
GeV break<br />
GeV-TeV break
<strong>W30</strong>
<strong>W30</strong> complex<br />
•<strong>SNR</strong> G8.7-0.1 (<strong>W30</strong>)<br />
•<strong>SNR</strong> G8.31-0.09<br />
•Suzaku source 1 / 2<br />
•PSR B1800-21/PWN<br />
……
OH maser<br />
Suzaku 1 / 2<br />
<strong>The</strong>rmal X-rays<br />
G8.31-0.09<br />
HESS obs<br />
PSR…<br />
Castro & Slane 2010
X-rays in the field of <strong>W30</strong><br />
•PSR B1800-21/PWN<br />
•Suzaku Source 1:<br />
unresolved; photon index -0.3<br />
favors HMXB explanation.<br />
•Suzaku Source 2:<br />
extended; photon index 1.7 with highly<br />
absorbed column density.
SED of <strong>W30</strong><br />
Higashi et al. 2008
GeV break GeV-TeV break
Summary of features<br />
•Middle-aged <strong>SNR</strong>s<br />
•MCs associated with.<br />
•Extended X-ray sources at the center of HESS<br />
sources.<br />
•Extremely high absorption column density for the<br />
X-rays sources.<br />
•High value of the ratio of TeV to X-ray flux<br />
F T /F X >10<br />
•Spectral break in GeV <strong>and</strong> GeV-TeV b<strong>and</strong>.<br />
•Soft spectral index in TeV: 2.5-2.7.
Possible explainations<br />
•PWN?<br />
high value of the ratio of TeV to X-ray flux<br />
F T/F X>10 suggests MF is as weak as 1μG!<br />
•<strong>SNR</strong> primary electrons?<br />
Old ages of these two <strong>SNR</strong>s disfavor this<br />
scenario.<br />
•<strong>SNR</strong>-MC induced gamma-rays together<br />
with X-rays produced by secondary<br />
electrons?
Diffusion-illumination case?<br />
Just like W28?<br />
Break! Break! Break! Break!
<strong>SNR</strong>-MC<br />
• One cloud or two clouds?<br />
1. One-cloud case needs large mass of<br />
MC>10^6 M_sun<br />
2. <strong>The</strong> separation of GeV <strong>and</strong> TeV emission<br />
favor two-cloud case.<br />
Further evidences are needed in observation,<br />
especially for explicit CO observation.
Thank you!
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