Gamma-Ray Spectra and Variability of the Crab Nebula Emission Observed by BATSE
Gamma-Ray Spectra and Variability of the Crab Nebula Emission Observed by BATSE
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BATSE 观测到的蟹状星云发射的伽马射线光谱和变化
DOI：
10.1086/378700
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发表时间：
2003
期刊：
影响因子：
--
通讯作者：
W. Wheaton
中科院分区：
文献类型：
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作者：
J. Ling;W. Wheaton
我们报告了 1991 年 5 月 24 日（TJD 8400）到 1994 年 10 月 3 日（TJD 9628）期间约 600 天的 BATSE 地球掩星观测，观测到蟹状星云发射的总伽马射线（30 keV 至 1.7 MeV）。 35-100、100-200、200-300、300-400、400-700 和 700-1000 keV 的光变曲线表明，BATSE 在这六个能带中的每一个中检测到正通量，其显着性分别约为 31、20、9.2、4.5、2.6 和 1.3 σ。一天。我们还在 35-300 keV 能量区域观察到显着的通量和光谱变化，时间尺度为几天到几周。低于 300 keV 的光谱，在典型的康普顿伽马射线天文台 6-13 天的观测周期内平均，可以通过平均指数为 ~2.1 和 ~2.4 的破坏幂律很好地描述，在 ~100 keV 的光谱断裂附近变化。在 300 keV 以上，三个 400 天周期（分别为 TJD 8400-8800、8800-9200 和 9200-9628）的长期平均光谱可以很好地由指数为 ~2.34 到 ~670 keV 的相同幂律很好地表示，加上从 ~670 keV 延伸到 ~1.7 MeV 的硬光谱分量，光谱指数为 〜1.75。后一个成分可能与 COMPTEL 在 0.7-3 MeV 范围内观察到的复杂结构有关。在 3 MeV 以上，由低能 BATSE 谱确定的幂律连续体的外推与 COMPTEL 在 3-25 MeV 范围内测量的通量以及 EGRET 在 30-50 MeV 范围内测量的通量一致。我们将这些结果解释为脉冲星喷射的粒子与星云系统不同动力区域的场相互作用产生的同步加速器发射，正如哈勃太空望远镜、XMM-牛顿和钱德拉最近观察到的那样。
We report ~600 days of BATSE earth occultation observations of the total gamma-ray (30 keV to 1.7 MeV) emission from the Crab Nebula between 1991 May 24 (TJD 8400) and 1994 October 3 (TJD 9628). Light curves from 35-100, 100-200, 200-300, 300-400, 400-700, and 700-1000 keV show that positive fluxes were detected by BATSE in each of these six energy bands at significances of approximately 31, 20, 9.2, 4.5, 2.6, and 1.3 σ, respectively, per day. We also observed significant flux and spectral variations in the 35-300 keV energy region, with timescales of days to weeks. The spectra below 300 keV, averaged over typical Compton Gamma Ray Observatory viewing periods of 6-13 days, can be well described by a broken power law with average indices of ~2.1 and ~2.4, varying around a spectral break at ~100 keV. Above 300 keV, the long-term averaged spectra, averaged over three 400 day periods (TJD 8400-8800, 8800-9200, and 9200-9628, respectively), are well represented by the same power law with index of ~2.34 up to ~670 keV, plus a hard spectral component extending from ~670 keV to ~1.7 MeV, with a spectral index of ~1.75. The latter component could be related to a complex structure observed by COMPTEL in the 0.7-3 MeV range. Above 3 MeV, the extrapolation of the power-law continuum determined by the low-energy BATSE spectrum is consistent with fluxes measured by COMPTEL in the 3-25 MeV range and by EGRET from 30-50 MeV. We interpret these results as synchrotron emission produced by the interaction of particles ejected from the pulsar with the field in different dynamical regions of the nebula system, as observed recently by the Hubble Space Telescope, XMM-Newton, and Chandra.