The known members of the class of hyperluminous X-ray sources (HLXs) are few in number, yet they are of great interest as they are regarded as the likeliest intermediate-mass black hole (IMBH) candidates amongst the wider population of ultraluminous X-ray sources (ULXs). Here we report optical photometry and spectroscopy of a HLX candidate associated with the galaxy IC 4320, that reveal it is a background AGN. We discuss the implications of the exclusion of this object from the small number of well-studied HLXs, that appears to accentuate the difference in characteristics between the good IMBH candidate ESO 243-49 HLX-1 and the small handful of other HLXs.
Cite
@article{arxiv.1503.01711,
title = {The hyperluminous X-ray source candidate in IC 4320: another HLX bites the dust},
author = {Andrew D Sutton and Timothy P. Roberts and Jeanette C. Gladstone and Dominic J. Walton},
journal= {arXiv preprint arXiv:1503.01711},
year = {2015}
}
Comments
7 pages, 4 figures, accepted for publication in MNRAS