A Suzaku Study of Ejecta Structure and Origin of Hard X-Ray Emission in the Supernova Remnant G 156.2+5.7
A Suzaku Study of Ejecta Structure and Origin of Hard X-Ray Emission in the Supernova Remnant G 156.2+5.7
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DOI：
10.1093/pasj/64.3.61
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发表时间：
2012-05
影响因子：
2.3
通讯作者：
H. Uchida;H. Tsunemi;S. Katsuda;K. Mori;R. Petre;H. Yamaguchi
中科院分区：
文献类型：
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作者：
H. Uchida;H. Tsunemi;S. Katsuda;K. Mori;R. Petre;H. Yamaguchi
我们报告了一个X射线研究的进化银河超新星遗迹（SNR）G156.2+5.7的基础上，六个指向观测朱雀。遗迹的大范围（直径100弧分）使我们能够从表观中心研究其西北和东部方向的放射状结构。的X射线光谱很好地符合一个两个组成部分的非平衡电离模型，代表扫了星际介质（ISM）和富含金属的喷出物。我们发现突出的Si，S和Fe从喷出物组分的中心浓度; O，Ne和Mg的轻元素分布更均匀。ISM分量的温度表明是一个缓慢的冲击（610-960 km/s ^{-1}$），因此残余物的年龄估计为7，000 - 15，000年，假设其距离为1.1 kpc。G156.2+5.7也被认为会发出坚硬的非热X射线，尽管它比任何其他这样的遗迹都要古老得多。为了回应最近发现的背景星系团（2XMM J045637.2+522411），我们仔细排除了它的贡献，并重新检查了硬X射线发射的起源。我们发现，残留的硬X射线发射与宇宙X射线背景的预期水平是一致的。因此，从G156.2+5.7中未获得非热发射的可靠证据。这些结果与演进的SNR的图片是一致的。
We report an X-ray study of the evolved Galactic supernova remnant (SNR) G156.2+5.7 based on six pointing observations with Suzaku. The remnant's large extent (100$\arcmin$ in diameter) allows us to investigate its radial structure in the northwestern and eastern directions from the apparent center. The X-ray spectra were well fit with a two-component non-equilibrium ionization model representing the swept-up interstellar medium (ISM) and the metal-rich ejecta. We found prominent central concentrations of Si, S and Fe from the ejecta component; the lighter elements of O, Ne and Mg were distributed more uniformly. The temperature of the ISM component suggests a slow shock (610-960 km s$^{-1}$), hence the remnant's age is estimated to be 7,000-15,000 yr, assuming its distance to be $\sim$1.1 kpc. G156.2+5.7 has also been thought to emit hard, non-thermal X-rays, despite being considerably older than any other such remnant. In response to a recent discovery of a background cluster of galaxies (2XMM J045637.2+522411), we carefully excluded its contribution, and reexamined the origin of the hard X-ray emission. We found that the residual hard X-ray emission is consistent with the expected level of the cosmic X-ray background. Thus, no robust evidence for the non-thermal emission was obtained from G156.2+5.7. These results are consistent with the picture of an evolved SNR.