Hitomi X-ray observation of the pulsar wind nebula G21.5-0.9
Hitomi X-ray observation of the pulsar wind nebula G21.5-0.9
复制标题
瞳X射线观测脉冲星风星云G21.5-0.9
DOI：
10.1093/pasj/psy027
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发表时间：
2018
影响因子：
2.3
通讯作者：
et al (他191名）
中科院分区：
文献类型：
--
作者：
Hitomi Collaboration;Aharonian Felix;...;Kohmura Takayoshi...;et al (他191名）
我们介绍了Hitomi对一个年轻的复合型超新星遗迹（SNR）G21.5−0.9的X射线观测结果，其发射主要由脉冲星风星云（PWN）贡献。用软X射线光谱仪（SXS）、软X射线成像仪和硬X射线成像仪（HXI）获得的0.8-80 keV范围内的X射线光谱显示出与先前用努斯塔观测发现的连续谱中的显著中断。在考虑了SNR的所有已知发射而不是PWN本身之后，我们发现Hitomi光谱可以符合破幂律，其中光子指数为Γ1= 1.74 ± 0.02和Γ2= 2.14 ± 0.01，低于和高于7.1 ± 0.3 keV处的破幂律，这显著低于努斯塔的结果（79.0 keV）。光谱中断不能再现随时间变化的粒子注入单区光谱能量分布模型，这强烈表明，需要一个更复杂的发射模型，建议由最近的理论模型。我们还用SXS寻找窄的发射或吸收谱线，并用HXI和软伽马射线探测器对PSR J1833−1034进行时序分析。脉冲星没有发现明显的脉动。然而，出乎意料的是，在SXS数据中在4.2345 keV和9.296 keV处检测到窄吸收线特征，显著性为3.65 σ。虽然这些特征的起源尚不清楚，但它们的检测开辟了一个新的研究领域，并且只有在X射线微量热计提供的高分辨率，灵敏度和测量扩展源的能力下才有可能。
We present results from the Hitomi X-ray observation of a young composite-type supernova remnant (SNR) G21.5−0.9, whose emission is dominated by the pulsar wind nebula (PWN) contribution. The X-ray spectra in the 0.8–80 keV range obtained with the Soft X-ray Spectrometer (SXS), Soft X-ray Imager, and Hard X-ray Imager (HXI) show a significant break in the continuum as previously found with the NuSTAR observation. After taking into account all known emissions from the SNR other than the PWN itself, we find that the Hitomi spectra can be fitted with a broken power law with photon indices of Γ1= 1.74 ± 0.02 and Γ2= 2.14 ± 0.01 below and above the break at 7.1 ± 0.3 keV, which is significantly lower than the NuSTAR result (∼9.0 keV). The spectral break cannot be reproduced by time-dependent particle injection one-zone spectral energy distribution models, which strongly indicates that a more complex emission model is needed, as suggested by recent theoretical models. We also search for narrow emission or absorption lines with the SXS, and perform a timing analysis of PSR J1833−1034 with the HXI and the Soft Gamma-ray Detector. No significant pulsation is found from the pulsar. However, unexpectedly, narrow absorption line features are detected in the SXS data at 4.2345 keV and 9.296 keV with a significance of 3.65 σ. While the origin of these features is not understood, their mere detection opens up a new field of research and was only possible with the high resolution, sensitivity, and ability to measure extended sources provided by an X-ray microcalorimeter.