GRS 1915+105的X射线能谱分析及黑洞自旋测量  

X-ray Energy Spectra Study and Black Hole Spin Estimate of GRS 1915+105

作　　者：王苑 苟利军 赵雪杉 冯叶 贾楠 廖振玄 李玉丰 WANG Yuan;GOU Li-jun;ZHAO Xue-shan;FENG Ye;JIA Nan;LIAO Zhen-xuan;LI Yu-feng(National Astronomical Observatories,Chinese Academy of Sciences,Beijing 100101;Key Laboratory for Computational Astrophysics,National Astronomical Observatories,Chinese Academy of Sciences,Beijing 100012;School of Astronomy and Space Sciences,University of Chinese Academy of Sciences,Beijing 100049)

机构地区：[1]中国科学院国家天文台,北京100101 [2]中国科学院国家天文台计算天体物理重点实验室,北京100012 [3]中国科学院大学天文与空间科学学院,北京100049

出　　处：《天文学报》2023年第2期21-29,共9页Acta Astronomica Sinica

基　　金：国家自然科学基金项目(U1838114);科技部重点研发项目(2016YFA0400801)资助。

摘　　要：GRS 1915+105是银河系内的低质量黑洞X射线双星,其能谱和黑洞自旋已经得到了广泛的研究.自2018年6月开始,其X射线流量下降到了低流量水平,其间偶尔会产生多波段的耀发.利用Insight-HXMT(Insight-Hard X-ray Modulation Telescope,简称为慧眼)卫星在2020年8月30日到2020年10月13日之间对GRS1915+105的观测数据,研究了其能谱特性,发现在此次爆发过程中, X射线能谱可以用一个康普顿化的多温黑体谱很好地拟合.整个爆发的硬度强度图(Hardness-Intensity Diagram, HID)一直处于软态.采用GRS1915+105的最新动力学参数M=12.4_(-1.8)^(+2.0)M⊙, i=60°±5°, D=8.6_(-1.6)^(+2.0)kpc (M、M⊙、i和D分别表示黑洞质量、太阳质量、盘倾角和距离),得到其无量纲黑洞自旋a*的一个下限a*> 0.9990,确认了GRS 1915+105是一个具有极端自旋的黑洞.考虑本地吸收体的作用,在模型中加入了吸收成分“tbpcf”(表示一个被部分遮蔽的吸收成分模型),其等效氢柱密度高达10^(23)cm^(-2),与“康普顿厚”的特征一致.GRS 1915+105 is a galactic low-mass X-ray binary.Its energy spectra and black hole spin have been extensively studied.Since 2018 July,it has declined into a low-flux X-ray level,occasionally interrupted by multi-wavelength flares.Using the data of Insight-HXMT(Insight-Hard X-ray Modulation Telescope)satellite from August 30 to Oct 13,2020,the energy spectra characteristics of GRS 1915+105 is investigated.The results show that the energy spectra can be well fitted with a Comptonized multi-temperature blackbody model.The evolution of the hardness-intensity diagram during the outburst remains in the soft state.Adopting new dynamical parameters of GRS 1915+105(including the black hole mass M,the Sun mass M⊙,the inclination angle i,and the distance d):M=12.4_(-1.8)^(+2.0) M⊙,i=60◦±5◦,D=8.6_(-1.6)^(+2.0) kpc,the group obtains a lower limit of the black hole spin,a∗>0:9990,confirming that GRS 1915+105 is an extremely-spinning black hole.Considering the effects of a local absorber,the group adds the absorption component“tbpcf”into the model.Its equivalent hydrogen column density reaches 10^(23) cm^(−2),which is consistent with the characteristics of“Compton-thick”.

关 键 词：恒星:黑洞 X射线:双星 黑洞物理 

分 类 号：P145[天文地球—天体物理]