论文标题
使用Astrosat的中子恒星低质量X射线二进制4U 1724-30的探测光谱和时间演变
Probing spectral and temporal evolution of the neutron star low-mass X-ray binary 4U 1724-30 with AstroSat
论文作者
论文摘要
我们使用软X射线望远镜（SXT）和大面积X射线比例计数器（LAXPC）仪器（LAXPC）Instruments在板Astrosat上的宽带频谱研究宽带光谱研究（NS）低质量X射线二元（LMXB）4U 1724-30。在2017年，Astrosat在4个时期内观察到了昏暗的LMXB源，所有这些都对应于以频谱进化为主的低亮度非热发射（硬/岛）发射状态。所有X射线宽带光谱都可以通过NS边界层（BL）或NS表面的热发射和非热发射分量的组合来建模，这可能是由圆盘种子光子的逆构造来建立的。我们研究了频率和能量依赖性变化的存在，以探测椎间盘/冠状动脉波动的起源。我们还报告了显示光球半径膨胀（PRE）的I型X射线突发的检测。在爆发期间，在30-80 KEV能量频段中严重的X射线短缺以及持续发射的增强揭示了对整体积聚过程的爆发反馈。使用触摸式的爆发通量$ \ sim $ $ $ 4.25 \ times 10^{ - 8} $ erg s $^{ - 1} $ cm $^{ - 2} $，源的距离估计为$ \ sim $ 8.4 kpc。
We report the broadband spectro-temporal study of the poorly studied accreting neutron star (NS) low mass X-ray binary (LMXB) 4U 1724-30 using data from Soft X-ray Telescope (SXT) and Large Area X-ray Proportional Counters (LAXPC) instruments on board AstroSat. The dim persistent LMXB source was observed with AstroSat over 4 epochs in 2017, all of which corresponded to a low-luminosity non-thermal emission dominated (hard/island) emission state with modest spectral evolution. All the X-ray broadband spectra can be modelled by a combination of thermal emission from the NS boundary layer (BL) or NS surface and a non-thermal emission component possibly originating from the inverse Comptonization of the disc seed photons. We investigate the presence of frequency and energy-dependent variabilities to probe the origin of the disc/coronal fluctuations. We also report the detection of a Type-I X-ray burst displaying a photospheric radius expansion (PRE). During the burst, a hard X-ray shortage in the 30-80 keV energy band and the enhancement of the persistent emission reveal the burst feedback on the overall accretion process. Using the touch-down burst flux $\sim$ $4.25 \times 10^{-8}$ erg s$^{-1}$ cm$^{-2}$, the distance of the source is estimated as $\sim$ 8.4 kpc.
