A Transient Black Hole Low-Mass X-Ray Binary Candidate in Centaurus A Journal Articles uri icon

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  • We report the discovery of a bright transient X-ray source, CXOU J132518.2-430304, towards Centaurus A (Cen A) using six new Chandra X-Ray Observatory observations in 2007 March--May. Between 2003 and 2007, its flux has increased by a factor of >770. The source is likely a low-mass X-ray binary in Cen A with unabsorbed 0.3-10 keV band luminosities of (2-3) x 10^{39} erg s^-1 and a transition from the steep-power law state to the thermal state during our observations. CXOU J132518.2-430304 is the most luminous X-ray source in an early-type galaxy with extensive timing information that reveals transience and a spectral state transition. Combined with its luminosity, these properties make this source one of the strongest candidates to date for containing a stellar-mass black hole in an early-type galaxy. Unless this outburst lasts many years, the rate of luminous transients in Cen A is anomalously high compared to other early-type galaxies.


  • Sivakoff, GR
  • Kraft, RP
  • Jordán, A
  • Juett, AM
  • Evans, DA
  • Forman, WR
  • Hardcastle, MJ
  • Sarazin, CL
  • Birkinshaw, M
  • Brassington, NJ
  • Croston, JH
  • Harris, William Edgar
  • Jones, C
  • Murray, SS
  • Raychaudhury, S
  • Woodley, KA
  • Worrall, DM

publication date

  • April 10, 2008