arXivDaily arXiv每日学术速递 周一至周五更新
arXiv 2306.00545astro-ph.HE
收藏

新发现中子星X射线双星Swift J1858.6-0814的复杂光谱行为

The complex spectral behavior of the newly discovered neutron star X-ray binary Swift J1858.6-0814

Aditya S. Mondal, B. Raychaudhuri, Gulab C Dewangan

AI总结:

本文报告了新发现中子星X射线双星Swift J1858.6-0814的NuSTAR观测结果,通过时间分辨光谱分析发现其存在显著盘截断,并利用相对论反射模型和部分覆盖吸收模型解释了观测到的复杂光谱特征。

摘要:

我们报告了2019年3月23日对新发现的中子星X射线双星Swift J1858.6-0814进行的NuSTAR观测结果。该源的光曲线在本次观测的部分时间间隔内表现出几次大耀发。在主要发生大耀发活动的高强度间隔内,该源较软。我们通过提取两个不同强度间隔的光谱对该源进行了时间分辨光谱分析。假设距离为15 kpc,在高强度和低强度间隔内,观测到该源的3-79 keV光度分别约为9.68×10^36 ergs/s和4.78×10^36 ergs/s。我们发现吸收柱密度值很大(N_H约1.1×10^23 cm^-2),且似乎与该源的观测通量不相关。每个光谱在5-7 keV能段显示出Fe Kα发射的证据,在约7-8 keV处有一个吸收边,以及在15 keV以上有一个宽康普顿隆起,表明存在反射光谱。观测到的特征可以通过相对论反射模型和部分覆盖吸收模型的贡献得到很好的解释。根据最佳拟合光谱模型,我们发现内盘半径为4.87_{-0.96}^{+1.63} R_ISCO(高强度间隔)和5.68_{-2.78}^{+9.54} R_ISCO(低强度间隔),表明存在显著的盘截断。盘倾角相对较低,i<33度。考虑到盘在磁层半径处被截断,我们进一步给出了该源磁场强度的上限。

英文摘要:

We report on the \nustar{} observation of the newly discovered neutron star X-ray binary Swift~J1858.6-0814 taken on 23rd March 2019. The light curve of the source exhibits several large flares during some time intervals of this observation. The source is softer in the high-intensity interval where the large flaring activity mainly occurs. We perform time-resolved spectroscopy on the source by extracting spectra for two different intensity intervals. The source was observed with a $3-79 \kev{}$ luminosity of $\sim 9.68\times 10^{36}$ ergs/s and $\sim 4.78\times 10^{36}$ ergs/s for high and low-intensity interval, respectively assuming a distance of $15$ kpc. We find a large value of the absorbing column density ($\rm{N_{H}}\sim 1.1\times 10^{23}$ cm$^{-2}$), and it appears to be uncorrelated with the observed flux of the source. Each spectrum shows evidence of Fe K$α$ emission in the $5-7$\kev{} energy band, an absorption edge around $\sim 7-8$\kev{}, and a broad Compton hump above $15$\kev{}, indicating the presence of a reflection spectrum. The observed features are well explained by the contribution of a relativistic reflection model and a partially covering absorption model. From the best-fit spectral model, we found an inner disc radius to be $4.87_{-0.96}^{+1.63}\;R_{ISCO}$ (for the high-intensity interval) and $5.68_{-2.78}^{+9.54}\;R_{ISCO}$ (for the low-intensity interval), indicating a significant disc truncation. The disk inclination is found to be relatively low, $i< 33^{0}$. We further place an upper limit on this source's magnetic field strength considering the disc is truncated at the magnetospheric radius.

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。

↑