论文标题
LMC X-2的Astrosat视图：宽带X射线光谱特性的演变沿完整的Z轨道
AstroSat view of LMC X-2: Evolution of broadband X-ray spectral properties along a complete Z-track
论文作者
论文摘要
在本文中，我们报告了使用$ \ sim $ \ sim $ 140 ks观测值获得的，{\ it大面积x射线比例计数器（laxpc）}和{\ it soft x-ray telescope（sxt）}}}}。用{\ it laxpc}数据创建的HID显示了源的完整Z-Pattern，显示了所有三个分支。我们研究了Z-Track的宽带X射线光谱在$ 0.5-20.0 $ keV的宽带X射线光谱的演化，这是该来源的首次这样的研究。 Z-Pattern不同部分的X射线光谱通过吸收的成分成分很好地描述了。没有吸积盘组件的不存在表明该盘很可能被组成的区域遮盖了。发现最佳拟合电子温度（$ kt_e $）在$ 1.7-2.1 $ keV的范围内，并且发现光学深度（$τ$）的范围在$ 13.2-17.5 $的范围内。随着源从正常/燃烧分支（NB/FB）顶点移动到FB的上部，光学深度（$τ$）增加，这表明可能是由强辐射压力触发的可能的流出。 HB和NB的功率密度光谱（PDS）可以分别配备纯幂律$α$ $ $ \ sim $ 1.68和0.83。我们还发现了FB中QPO（2.8〜 $σ$）的弱证据。源的固有光度在$（1.03-1.79）$ $ \ times $ 10 $^{38} $ ergs/s之间变化。我们通过与其他Z源和LMC X-2的先前观察结果进行比较来讨论我们的结果。
In this paper, we report the first results of the extragalactic Z-source LMC X-2 obtained using the $\sim$ 140 ks observations with {\it Large Area X-ray Proportional Counter (LAXPC)} and {\it Soft X-ray Telescope (SXT)} onboard {\it AstroSat}. The HID created with the {\it LAXPC} data revealed a complete Z-pattern of the source, showing all the three branches. We studied the evolution of the broadband X-ray spectra in the energy range of $0.5-20.0$ keV along the Z-track, a first such study of this source. The X-ray spectra of the different parts of the Z-pattern were well described by an absorbed Comptonized component. An absence of the accretion disc component suggests that the disc is most probably obscured by a Comptonized region. The best fit electron temperature ($kT_e$) was found to be in the range of $1.7-2.1$ keV and optical depth ($τ$) was found to be in the range of $13.2-17.5$. The optical depth ($τ$) increased as the source moved from the normal/flaring branch (NB/FB) vertex to the upper part of the FB, suggesting a possible outflow triggered by a strong radiation pressure. The power density spectra (PDS) of HB and NB could be fitted with a pure power-law of index $α$ $\sim$ 1.68 and 0.83 respectively. We also found a weak evidence of QPO (2.8~$σ$) in the FB. The intrinsic luminosity of the source varied between $(1.03-1.79)$ $\times$ 10$^{38}$ ergs/s. We discuss our results by comparing with other Z-sources and the previous observations of LMC X-2.
