标题： 河外黑洞X射线双星LMC X-1和LMC X-3的多任务观测：宽带光谱特征的演化 显示英文标题

标题： Multi-mission view of extragalactic black hole X-ray binaries LMC X-1 and LMC X-3: evolution of broadband spectral features

摘要： 河外黑洞X射线双星LMC X-1和LMC X-3是持久源，通常处于软能谱态。 我们展示了使用MAXI、NICER、NuSTAR和AstroSat在2014年至2020年期间观测到的这些源的光谱和时间研究结果。 长期MAXI光变曲线的研究表明，LMCX-1的2-10keV通量分数波动中等（$\sim$20%），而LMCX-3的则较高（$\sim$50%）。 这两个源的能量谱都由一个盘黑体和一个康普顿化组分组成，其中LMCX-1还具有额外的Fe线发射特征。 NICER（0.3-10keV）、NuSTAR（3.0-40keV）和AstroSat（0.5-20keV）的光谱分析共同显示LMC X-1在整个2014-2020年间一直保持在软态（盘通量贡献$f_{disc}>80$%，光子指数$\Gamma\sim2.06-4.08$）。 从bolometric光度（0.1-50keV）计算出的LMC X-1的吸积率$\dot{M}$被发现位于$0.07-0.24\dot{M}_{Edd}$（爱丁顿吸积率）以内。 尽管LMC X-3在大多数时间里处于软态（$f_{disc}>95\%,\Gamma\sim2.3$），但它表现出向中间态 （$f_{disc}=47-73\%,\Gamma\sim2.02-2.36$）和硬态 （$f_{disc}\sim26\%,\Gamma\sim1.6$）的转变。 LMC X-3通过不同光谱态的光变幅度在 （$\dot{M}$）至 （$0.01-0.42\dot{M}_{Edd}$）之间变化。 时序研究表明，0.3-10 keV范围内的功率密度谱（PDS）对于LMC X-1呈现红噪声，均方根值为2%，而对于LMC X-3，在软态时为0.08-2.35%，但在中间态（3.05-4.91%）和硬态（$\sim$17.06%）时相对较高。 通过连续拟合法，我们限制了LMC X-1和LMC X-3的自旋分别在0.85-0.94和0.16-0.33范围内，而通过Fe线拟合法，发现LMC X-1的自旋为0.93-0.94。 最后，我们讨论了我们的发现对黑洞附近吸积盘动力学的影响。 显示英文摘要

摘要： Extragalactic black hole X-ray binaries LMC X-1 and LMC X-3 are the persistent sources, usually found in soft spectral state. We present the results from spectral and timing study of these sources using MAXI, NICER, NuSTAR and AstroSat observations carried out during 2014-2020. Study of long-term MAXI lightcurve shows that the fractional variability of flux in 2-10keV is moderate ($\sim$20%) in LMCX-1 and high ($\sim$50%) in LMCX-3. The energy spectra of both sources are characterized by a disc blackbody and a Comptonization component with LMCX-1 having an additional Fe-line emission feature. NICER (0.3-10keV), NuSTAR (3.0-40keV) and AstroSat (0.5-20keV) spectral analysis collectively show that LMC X-1 remained in the soft state (disc flux contribution $f_{disc}>80$%, photon index$\Gamma\sim2.06-4.08$) throughout 2014-2020. Mass accretion rate, $\dot{M}$ of LMC X-1 calculated from bolometric luminosity (0.1-50keV) is found to be within $0.07-0.24\dot{M}_{Edd}$ (Eddington mass accretion rate). Although LMC X-3 remained in the soft state ($f_{disc}>95\%,\Gamma\sim2.3$) during most of the time, it exhibits transition into intermediate ($f_{disc}=47-73\%,\Gamma\sim2.02-2.36$) and hard state ($f_{disc}\sim26\%,\Gamma\sim1.6$). $\dot{M}$ of LMC X-3 through different spectral states varies within $0.01-0.42\dot{M}_{Edd}$. Temporal study show that the Power Density Spectra (PDS) in 0.3-10keV follow a red-noise with rms of 2% for LMC X-1 and in case of LMC X-3, it is 0.08-2.35% during the soft state, but relatively high in the intermediate(3.05-4.91%) and hard state($\sim$17.06%). From continuum-fitting method we constrain spin of LMC X-1 and LMC X-3 to be within 0.85-0.94 and 0.16-0.33 respectively and from Fe-line fitting method, spin of LMC X-1 is found to be 0.93-0.94. Finally, we discuss the implication of our findings in the context of accretion disc dynamics around the vicinity of the BHs.