Back to Business: SLX 1746–331 after 13 Years of Silence

Abstract The black hole candidate system SLX 1746–331 was back to business in 2023, after a long silence of roughly 13 years. An outburst observed thoroughly by Insight-HXMT and NICER. is characterized spectral dominance the soft state, where joint NICER analysis shows temperature dependence disk flux follows T in 3.98 , thus suggests that inner reaches its innermost stable circular orbit during almost entire outburst. By assuming 0.3 L Edd for peak an inclination angle zero degrees, lower limit compact object hosted this estimated as 3.28 ± 2.14 M ⊙ . We also look into relation between sample systems, taking derived 1746–331, such results mass estimation 5.2 4.5 Finally, spin constrained be larger than 0.8 with model KERRBB.