论文标题
中子恒星低质量X射线二进制4U 1735-44的尼斯塔尔观察结果
NICER-NuSTAR Observations of the Neutron Star Low-Mass X-ray Binary 4U 1735-44
论文作者
论文摘要
我们在2018年8月获得的第一个同时发生$ $ $和$ nustar $ $ nustar $观测值。源的发光度为$ \ sim1.8〜（d/5.6 \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ kpc}）^{2} \ times10^{37} $ ergs s $^{ - 1} $ in $ 0.4-30 $ kev band。我们用两种不同的连续描述来解释连续发射，这些描述已用于对源进行建模。尽管选择了连续模型，但组合的Pass带揭示了宽阔的Fe K线，指示频谱中的反射。为了说明反射光谱，我们利用了反射模型Relxill的修改版本，该版本是针对积聚NSS的热发射而定制的。另外，我们还使用RFXCONV的反射卷积模型来对构成的热成分产生的反射发射进行建模以进行比较。我们确定积聚磁盘的最内向区域在90％的置信度范围内延伸到最内向的稳定圆形轨道（$ r _ {\ Mathrm {isco}} $），无论反射模型如何。此外，当前的$ not $ $ $ nustar $/fpma（b）的通量校准在5％之内。
We report on the first simultaneous $NICER$ and $NuSTAR$ observations of the neutron star (NS) low-mass X-ray binary 4U 1735$-$44, obtained in 2018 August. The source was at a luminosity of $\sim1.8~(D/5.6\ \mathrm{kpc})^{2}\times10^{37}$ ergs s$^{-1}$ in the $0.4-30$ keV band. We account for the continuum emission with two different continuum descriptions that have been used to model the source previously. Despite the choice in continuum model, the combined passband reveals a broad Fe K line indicative of reflection in the spectrum. In order to account for the reflection spectrum we utilize a modified version of the reflection model RELXILL that is tailored for thermal emission from accreting NSs. Alternatively, we also use the reflection convolution model of RFXCONV to model the reflected emission that would arise from a Comptonized thermal component for comparison. We determine that the innermost region of the accretion disk extends close to the innermost stable circular orbit ($R_{\mathrm{ISCO}}$) at the 90% confidence level regardless of reflection model. Moreover, the current flux calibration of $NICER$ is within 5% of the $NuSTAR$/FPMA(B).
