An Off-nucleus Nonstellar Black Hole in the Seyfert Galaxy NGC 5252

Journal
Date Issued
2015
Author(s)
Kim, Minjin
•
Ho, Luis C.
•
Wang, Junfeng
•
Fabbiano, Giuseppina
•
BIANCHI, STEFANO
•
•
•
•
Wang, Chen
DOI
Description
We are grateful to an anonymous referee for helpful comments. We thank John Mulchaey and Elina Nieppola for useful suggestions and discussion. L.C.H. acknowledges support by the Chinese Academy of Science through grant No. XDB09030102 (Emergence of Cosmological Structures) from the Strategic Priority Research Program and by the National Natural Science Foundation of China through grant No. 11473002. J.W. and G.F. acknowledge NASA grant GO3-14117. J.W. acknowledges support from NSFC grants 11443003 and 11473021.
Abstract
We report the discovery of an ultraluminous X-ray source (ULX; CXO J133815.6+043255) in NGC 5252. This ULX is an off-nuclear point source, which is 22″ away from the center of NGC 5252, and has an X-ray luminosity of 1.5 × 1040 erg s-1. It is one of the rare examples of a ULX, which exhibits clear counterparts in radio, optical, and UV bands. A follow-up optical spectrum of the ULX shows strong emission lines. The redshift of the [O iii] emission line coincides with the systematic velocity of NGC 5252, suggesting that the ULX is gravitationally bound to NGC 5252. The flux of [O iii] appears to be correlated with both X-ray and radio luminosity in the same manner as ordinary active galactic nuclei (AGNs), indicating that the [O iii] emission is intrinsically associated with the ULX. Based on the multiwavelength data, we argue that the ULX is unlikely to be a background AGN. A more likely option is an accreting black hole with a mass of ≥slant {10}4 {M}☉ , which might be a stripped remnant of a merging dwarf galaxy.
Volume
814
Issue
1
Start page
8
Uri
Url
Issn Identifier
0004-637X
Ads BibCode
2015ApJ...814....8K
Rights
open.access
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