论文标题
超紧凑型X射线二进制4U 1543-624的同时和Nustar观察
Simultaneous NICER and NuSTAR Observations of the Ultra-compact X-ray Binary 4U 1543-624
论文作者
论文摘要
我们介绍了第一个联合nustar，并且对超紧凑型X射线二进制（UCXB）4U 1543 $ - $ 624在2020年4月获得。来源的发光度为$ l_ {0.5-50 \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ {2} {2} \ times10^{36} $ ergs s $ ngs s $^{ - 1} $，并显示了fe kum kum kum kum kum kump in os n os o n os n os o vi i vii and o vi i vii and o vi in comply， 光谱。我们使用了一个完整的反射模型，称为Xillverco，该模型是针对UCXBS中的非典型丰度量身定制的，以解释反射的发射。我们测试了O和Fe系组件的发射半径，并得出结论，它们源自积聚磁盘最内向区域的公共磁盘半径（$ r _ {\ rm in} \ leq1.07 \ r _ {\ r _ {\ r _ {\ mathrm {isco {isco}} $）。假设紧凑的吸积是中子星（NS），并且内盘的位置是alfvén半径，我们对磁场强度的上限为$ b \ leq0.7（d/7 \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ mathrm {kpc}）\ times10^{8} $ g在POLES上。鉴于缺乏检测到的脉动和$ r _ {\ rm in} $的位置，很可能是在ns表面和增生盘的内边缘之间形成边界层区域，范围为1.2 km。这意味着$ r _ {\ mathrm {ns}} \ leq 12.1 $ km的中子星的最大半径在假定规范NS质量为1.4 $ m _ {\ odot} $时。
We present the first joint NuSTAR and NICER observations of the ultra-compact X-ray binary (UCXB) 4U 1543$-$624 obtained in 2020 April. The source was at a luminosity of $L_{0.5-50\ \mathrm{keV}} = 4.9 (D/7\ \mathrm{kpc})^{2}\times10^{36}$ ergs s$^{-1}$ and showed evidence of reflected emission in the form of an O VIII line, Fe K line, and Compton hump within the spectrum. We used a full reflection model, known as xillverCO, that is tailored for the atypical abundances found in UCXBs, to account for the reflected emission. We tested the emission radii of the O and Fe line components and conclude that they originate from a common disk radius in the innermost region of the accretion disk ($R_{\rm in} \leq1.07\ R_{\mathrm{ISCO}}$). Assuming that the compact accretor is a neutron star (NS) and the position of the inner disk is the Alfvén radius, we placed an upper limit on the magnetic field strength to be $B\leq0.7(D/7\ \mathrm {kpc})\times10^{8}$ G at the poles. Given the lack of pulsations detected and position of $R_{\rm in}$, it was likely that a boundary layer region had formed between the NS surface and inner edge of the accretion disk with an extent of 1.2 km. This implies a maximum radius of the neutron star accretor of $R_{\mathrm{NS}}\leq 12.1$ km when assuming a canonical NS mass of 1.4 $M_{\odot}$.
