Diffuse X-ray emission from M101

被引:31
作者
Kuntz, KD
Snowden, SL
Pence, WD
Mukai, K
机构
[1] Univ Maryland Baltimore Cty, Dept Phys, Baltimore, MD 21250 USA
[2] NASA, High Energy Astrophys Lab, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA
关键词
galaxies : halos; galaxies; individual; (M101; NGC; 5457); galaxies : ISM; X-rays : diffuse background; X-rays : galaxies; X-rays : ISM;
D O I
10.1086/373947
中图分类号
P1 [天文学];
学科分类号
0704 ;
摘要
The total 0.45-1.0 keV luminosity of M101 is 3.2 x 10(39) ergs s(-1), of which 2.3 x 10(39) ergs s(-1) is due to diffuse emission. (Chandra observes only similar to60% of the diffuse emission observed by ROSAT because of its superior point-source detection.) Of the diffuse emission seen by Chandra, no more than 6% can be due to luminous unresolved point sources, such as X-ray binaries, and similar to10% is likely due to dwarf stars. The diffuse emission traces the spiral arms and is roughly correlated with the Halpha and far-UV emission. The radial distribution closely follows the optical profile. The bulk of the diffuse emission is characterized by a two-thermal component spectrum with kT = 0.20 and 0.75 keV, and the ratio of the emission measures of the two components is roughly constant as a function of both radius and surface brightness. The softer component has a sufficiently large covering factor that the bulk of the emission is likely extraplanar. We find no evidence of an extended axisymmetric X-ray halo, suggesting that any such halo has a strength much smaller than current predictions.
引用
收藏
页码:264 / 280
页数:17
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