Max Planck Institute for Astronomy, Heidelberg, Germany.
Department of Physics and Astronomy, University of Utah, Salt Lake City, UT, USA.
Nature. 2024 Jul;631(8020):285-288. doi: 10.1038/s41586-024-07511-z. Epub 2024 Jul 10.
Black holes have been found over a wide range of masses, from stellar remnants with masses of 5-150 solar masses (M), to those found at the centres of galaxies with M > 10M. However, only a few debated candidate black holes exist between 150M and 10M. Determining the population of these intermediate-mass black holes is an important step towards understanding supermassive black hole formation in the early universe. Several studies have claimed the detection of a central black hole in ω Centauri, the most massive globular cluster of the Milky Way. However, these studies have been questioned because of the possible mass contribution of stellar mass black holes, their sensitivity to the cluster centre and the lack of fast-moving stars above the escape velocity. Here we report the observations of seven fast-moving stars in the central 3 arcsec (0.08 pc) of ω Centauri. The velocities of the fast-moving stars are significantly higher than the expected central escape velocity of the star cluster, so their presence can be explained only by being bound to a massive black hole. From the velocities alone, we can infer a firm lower limit of the black hole mass of about 8,200M, making this a good case for an intermediate-mass black hole in the local universe.
黑洞的质量范围很广，从质量为 5 到 150 个太阳质量的恒星残骸，到质量大于 10M 的星系中心的黑洞。然而，在 150M 和 10M 之间只有少数有争议的候选黑洞存在。确定这些中等质量黑洞的种群是理解早期宇宙中超大质量黑洞形成的重要步骤。几项研究声称在银河系中质量最大的球状星团ω Centauri 中检测到一个中心黑洞。然而，由于恒星质量黑洞的可能质量贡献、对星团中心的敏感性以及缺乏高于逃逸速度的快速移动恒星，这些研究受到了质疑。在这里，我们报告了对 ω Centauri 中心 3 弧秒（0.08pc）内的七颗快速移动恒星的观测结果。这些快速移动恒星的速度明显高于星团的预期中心逃逸速度，因此只能通过与一个大质量黑洞的束缚来解释它们的存在。仅从速度来看，我们可以推断出黑洞质量的下限约为 8200M，这是一个很好的本地宇宙中存在中等质量黑洞的例子。
