Fast-moving stars around an intermediate-mass black hole in ω Centauri.
basic_science · Level V
Where this comes from
- Record sourced from PubMed, PMID 38987499.
- Also identified by DOI 10.1038/s41586-024-07511-z and PMC identifier 11236702.
- Licence recorded as CC BY.
- The licence permits redistribution, so the abstract is shown in full and the full text is available from the publisher.
Abstract
Black holes have been found over a wide range of masses, from stellar remnants with masses of 5-150 solar masses (M<sub>☉</sub>), to those found at the centres of galaxies with M > 10<sup>5</sup>M<sub>☉</sub>. However, only a few debated candidate black holes exist between 150M<sub>☉</sub> and 10<sup>5</sup>M<sub>☉</sub>. Determining the population of these intermediate-mass black holes is an important step towards understanding supermassive black hole formation in the early universe<sup>1,2</sup>. Several studies have claimed the detection of a central black hole in ω Centauri, the most massive globular cluster of the Milky Way<sup>3-5</sup>. 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<sup>6-9</sup>. 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<sub>☉</sub>, making this a good case for an intermediate-mass black hole in the local universe.