We study the spectral and temporal properties of the black hole (BH) X-ray transient binary SLX 1746–331 during the 2023 outburst with NICER, NuSTAR, and Insight-HXMT observations. Through the joint fitting of the spectra from NICER, NuSTAR, and Insight-HXMT, the spin and inclination angles are measured for the first time as 0.85 ± 0.03 and 53° ± 0.°5, respectively. Accordingly, the mass of the compact star is updated from the previous lower limit of 3.3 ± 2.1M _⊙ to 5.5 ± 3.6M _⊙, which is consistent with 5.2 ± 4.5M _⊙ measured with an empirical mass–luminosity correlation of BH samples. With more NICER observations covering the later decay of the outburst, we confirm that the entire outburst was dominated by the disk emissions, and the thermal spectrum follows F∝Tin3.974±0.003 , until a luminosity of over 2 magnitudes lower than the maximum of the outburst.

中文翻译：

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NICER、NuSTAR 和 Insight-HXMT 对黑洞 X 射线二进制 SLX 1746–331 的视图

我们通过 NICER、NuSTAR 和 Insight-HXMT 观测研究了 2023 年爆发期间黑洞 (BH) X 射线瞬态双星 SLX 1746-331 的光谱和时间特性。通过对NICER、NuSTAR和Insight-HXMT光谱的联合拟合，首次测得自旋角和倾角分别为0.85±0.03和53°±0.°5。相应地，致密星的质量从之前的下限3.3±2.1更新中号 _⊙至 5.5 ± 3.6中号 _⊙，与5.2±4.5一致中号 _⊙通过 BH 样本的经验质量-光度相关性进行测量。随着更多 NICER 观测涵盖爆发后期的衰变，我们确认整个爆发主要由圆盘发射主导，热谱如下 F∝时间在3.974±0.003 ，直到光度比爆发的最大值低超过2个星等。