2020/02/11 by Dacheng Lin, Jay Strader, Aaron J. Romanowsky +10 · 1 citation
Physics and Astronomy · #Astrophysical Phenomena and Observations #Astrophysics #Astrophysics and Cosmic Phenomena #Black hole (networking) #Computer network #Computer science #Physics #Pulsars and Gravitational Waves Research #astro-ph.GA #astro-ph.HE
paper · pdf · doi:10.3847/2041-8213/ab745b
Accepted for publication in ApJL, 5 pages, 4 figures
arxiv created 2020/02/11 · openalex publication_date 2020/03/31 · arxiv updated 2020/04/08 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/06
Abstract We recently discovered the X-ray/optical outbursting source 3XMM J215022.4−055108. It was best explained as the tidal disruption of a star by an intermediate-mass black hole of mass of a few tens of thousand solar masses in a massive star cluster at the outskirts of a large barred lenticular galaxy at D L = 247 Mpc. However, we could not completely rule out a Galactic cooling neutron star as an alternative explanation for the source. In order to further pin down the nature of the source, we have obtained new multiwavelength observations by XMM-Newton and the Hubble Space Telescope ( HST ). The optical counterpart to the source in the new HST image is marginally resolved, which rules out the Galactic cooling neutron star explanation for the source and suggests a star cluster of half-light radius ∼27 pc. The new XMM-Newton observation indicates that the luminosity was decaying as expected for a tidal disruption event and that the disk was still in the thermal state with a supersoft X-ray spectrum. Therefore, the new observations confirm the source as one of the best intermediate-mass black hole candidates.