The identification of an optical counterpart to the super-Eddington X-ray source NGC 5204 X-1 |
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Authors: | TP Roberts MR Goad MJ Ward RS Warwick PT O'Brien P Lira ADP Hands |
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Institution: | Department of Physics and Astronomy, University of Leicester, University Road, Leicester LE1 7RH |
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Abstract: | We report the identification of a possible optical counterpart to the super-Eddington X-ray source NGC 5204 X-1. New Chandra data show that the X-ray source is point-like, with a luminosity of 5.2×1039 erg s?1 (0.5–8 keV) . It displays medium- and long-term X-ray variability in observations spanning a period of 20 yr. The accurate Chandra position allows us to identify a blue optical continuum source ( m v =19.7) at the position of NGC 5204 X-1, using newly obtained optical data from the INTEGRAL instrument on the William Herschel Telescope. The X-ray and optical source properties are consistent with the scenario in which we are observing the beamed X-ray emission of a high-mass X-ray binary in NGC 5204, composed of an O star with either a black hole or neutron star companion. |
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Keywords: | galaxies: individual: NGC 5204 galaxies: stellar content X-rays: galaxies |
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