Stellar properties of the host galaxy of an ultraluminous X-ray source in NGC 5252. (22nd January 2020)

• Record Type: Journal Article
• Authors: Kim, Minjin; López, Kristhell M; Jonker, Peter G; Ho, Luis C; Im, Myungshin
• Is Part Of: Monthly notices of the Royal Astronomical Society. Volume 493:Number 1(2020)
• Page Start: L76
• Page End: L80
• Publication Date: 2020-01-22
• Subjects: black hole physics -- galaxies: active -- galaxies: individual: NGC 5252 -- galaxies: Seyfert -- X-rays: galaxies; Astronomy -- Research -- Periodicals; Periodicals; 520.5
• DOI: 10.1093/mnrasl/slaa011
• Languages: English
• ISSNs: 1745-3933

Abstract

ABSTRACT: An ultraluminous X-ray source (ULX) in NGC 5252 has been known as a strong candidate for an off-nuclear intermediate-mass black hole (IMBH). We present near-infrared imaging data of the ULX obtained with the William Herschel Telescope. Using this data we estimate a stellar mass associated with the ULX of ≈10 7.9 ± 0.1 $\, \mathrm{M}_\odot$, suggesting that it could be (the remnant of) a dwarf galaxy that is in the process of merging with NGC 5252. Based on a correlation between the mass of the central black hole (BH) and host galaxy, the ULX is powered by a 10 5 $\, \mathrm{M}_\odot$ BH. Alternatively, if the BH mass is ≈10 6 $\, \mathrm{M}_\odot$ or larger, the host galaxy of the ULX must have been heavily stripped during the merger. The ULX K s -band luminosity is two orders of magnitude smaller than that expected from an ordinary active galactic nucleus with the observed [O iii ] luminosity, which also suggests the ULX lacks a dusty torus. We discuss how these findings provide suggestive evidence that the ULX is hosting an IMBH.