论文标题

关于在黑洞瞬态GRS的硬态状态下的软伽马射线发射的性质1716-249

On the nature of the soft gamma-ray emission in the hard state of the black hole transient GRS 1716-249

论文作者

Bassi, T., Malzac, J., Del Santo, M., Jourdain, E., Roques, J. -P., D'Aì, A., Miller-Jones, J. C. A., Belmont, R., Motta, S. E., Segreto, A., Testa, V., Casella, P.

论文摘要

在2016 - 2017年爆发期间,Black Hole Transient GRS 1716-249从广播到伽马射线频段进行监测。本文着重于2017年2月3月获得的光谱能量分布(SED),当时GRS 1716-249处于明亮的硬光谱状态。使用积分/SPI望远镜收集的软γ射线数据显示,存在频谱分量,该光谱成分超过了热成分发射。该组件通常被解释为X射线电晕中一小部分非热电子的逆综合构成发射。我们发现,混合热/非热组合模型可与GRS 1716-249的X/Gamma-ray频谱非常合适。最佳拟合参数是在其他黑洞X射线二进制文件中观察到的明亮硬状态光谱的典型特征。此外,磁化混合组合模型Belm对冠状磁场的强度约为1E+06 G的强度。或者,这种软伽马射线发射可能起源于无线电射流中的同步加速器发射。为了检验这一假设,我们将SED与辐照的盘和组合模型结合使用,并结合了射流内部冲击发射模型ISHEM。我们发现,具有P〜2.1电子分布的射流可以再现GRS 1716-249的软伽马射线发射。但是,如果我们在10 keV附近引入了预期的冷却中断,则射流模型将无法再解释观察到的软伽马射线发射,除非电子能量分布的指数更加困难(p <2)。

The black hole transient GRS 1716-249 was monitored from the radio to the gamma-ray band during its 2016-2017 outburst. This paper focuses on the Spectral Energy Distribution (SED) obtained in 2017 February-March, when GRS 1716-249 was in a bright hard spectral state. The soft gamma-ray data collected with the INTEGRAL/SPI telescope show the presence of a spectral component which is in excess of the thermal Comptonisation emission. This component is usually interpreted as inverse Compton emission from a tiny fraction of non-thermal electrons in the X-ray corona. We find that hybrid thermal/non-thermal Comptonisation models provide a good fit to the X/gamma-ray spectrum of GRS 1716-249. The best-fit parameters are typical of the bright hard state spectra observed in other black hole X-ray binaries. Moreover, the magnetised hybrid Comptonisation model BELM provides an upper limit on the intensity of the coronal magnetic field of about 1E+06 G. Alternatively, this soft gamma-ray emission could originate from synchrotron emission in the radio jet. In order to test this hypothesis, we fit the SED with the irradiated disc plus Comptonisation model combined with the jet internal shock emission model ISHEM. We found that a jet with an electron distribution of p~2.1 can reproduce the soft gamma-ray emission of GRS 1716-249. However, if we introduce the expected cooling break around 10 keV, the jet model can no longer explain the observed soft gamma-ray emission, unless the index of the electron energy distribution is significantly harder (p<2).

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