利用 MUSE 研究 Omega 中心的二进制系统: II. 对轨道周期分布的观测约束

Omega 中心 ($\omega$ Cen) 是银河系中最复杂的星团之一, 可能是被剥离的矮星系的核。由于其可能包含中间质量黑洞 (intermediate-mass black hole, IMBH) 或由 stellar-mass black holes (BHs) 组成的中心黑洞集合而备受争论, $\omega$ Cen 已被广泛研究多年。我们的 work focuses on characterizing the properties of binary systems in $\omega$ Cen via multi-epoch MUSE spectroscopic observations spanning over eight years and covering much of its central regions (i.e. core radius)。我们未检测到任何 stellar-mass BH candidates orbiting luminous stars, although mock samples indicate a high sensitivity of our survey to such systems。This suggests that BHs orbiting stars may be rare in $\omega$ Cen or in wide orbits around low-mass companions (where our survey is 50% complete) or that the periods of such systems are longer than expected from cluster dynamics。Additionally, we constrained the orbital properties of 19 binary systems in the cluster, with periods ranging from fractions of a day up to several hundred days。We observe an excess of binaries with P $\ge$ 10 d and find evidence that the intrinsic period distribution of binaries in $\omega$ Cen differs from those predicted by cluster evolutionary models。