arXivDaily arXiv每日学术速递 周一至周五更新
arXiv 2202.07153astro-ph.HE
收藏

4U 1636 $-$ 536 I型X射线爆发期间坡印廷-罗伯逊阻力和盘反射证据的NICER观测

NICER observations of the evidence of Poynting-Robertson drag and disk reflection during type I X-ray bursts from 4U 1636$-$536

Guoying Zhao, Zhaosheng Li, Yuanyue Pan, Maurizio Falanga, Long Ji, Yupeng Chen, Shu Zhang

摘要:

I型X射线爆发是中子星(NS)表面吸积物质不稳定热核燃烧的结果。高能X射线光子在这种爆发期间的快速释放与周围的吸积盘相互作用,这由于坡印廷-罗伯逊阻力而提高了吸积速率,因此,爆发发射的一部分被反射。我们分析了2017年发生在NS低质量X射线双星4U 1636- 536中的两次光球半径膨胀爆发,使用的数据来自中子星内部成分探测器。时间分辨的爆发光谱显示出明显的偏离黑体模型。通过引入增强的持续辐射($f_a$模型)或吸积盘的反射(\texttt{relxillNS}模型),可以显著改善光谱拟合。与\texttt{relxillNS}模型相比,$f_a$模型提供了更高的黑体温度和更高的爆发通量。$f_a$模型的两个爆发,$4.36\times10^{-8}~\mathrm{erg~cm^{-2}~s^{-1}}$和$9.10\times10^{-8}~\mathrm{erg~cm^{-2}~s^{-1}}$,峰值流量略高于爱丁顿极限的混合氢氦和纯氦爆发从以前的观测,分别。当同时考虑圆盘反射时,峰值通量较低以匹配优选值。我们发现的证据支持这两个X射线爆发的Poynting-Robertson阻力和磁盘反射已经出现的发现。此外,盘反射可贡献总突发发射的$\sim20-30\%$。

英文摘要:

Type I X-ray bursts are the result of an unstable thermonuclear burning of accreting matter on the neutron star (NS) surface. The quick release of energetic X-ray photons during such bursts interacts with the surrounding accretion disk, which raises the accretion rate due to Poynting-Robertson drag and, thus, a fraction of the burst emission is reflected. We analyzed two photospheric radius expansion bursts in the NS low-mass X-ray binary 4U 1636--536 that took place in 2017, using data from Neutron star Interior Composition Explorer. The time-resolved burst spectra showed clear deviations from a blackbody model. The spectral fitting can be significantly improved by introducing either the enhanced persistent emission (the $f_a$ model) or the reflection from the accretion disk (the \texttt{relxillNS} model). The $f_a$ model provides a higher blackbody temperature and higher burst flux compared with the \texttt{relxillNS} model. The peak fluxes of two bursts from the $f_a$ model, $4.36\times10^{-8}~\mathrm{erg~cm^{-2}~s^{-1}}$ and $9.10\times10^{-8}~\mathrm{erg~cm^{-2}~s^{-1}}$, are slightly higher than the Eddington limits of mixed hydrogen-helium and pure helium bursts from previous observations, respectively. When the disk reflections have been taken into account simultaneously, the peak fluxes are lower to match the preferred values. We find evidence to support the finding that both the Poynting-Robertson drag and disk reflection have been appeared during these two X-ray bursts. Moreover, the disk reflection may contribute $\sim20-30\%$ of the total burst emissions.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

↑