Spectral state transitions of the Ultraluminous X-ray Source IC 342 X-1

H. Marlowe, P. Kaaret, C. Lang, H. Feng, F. Grisé, N. Miller, D. Cseh, S. Corbel, R. F. Mushotzky

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15 Scopus citations


We observed the Ultraluminous X-ray Source (ULX) IC 342 X-1 simultaneously in X-ray and radio with Chandra and the JVLA to investigate previously reported unresolved radio emission coincident with the ULX. The Chandra data reveal a spectrum that is much softer than observed previously and is well modelled by a thermal accretion disc spectrum. No significant radio emission above the rms noise level was observed within the region of the ULX, consistent with the interpretation as a thermal state though other states cannot be entirely ruled out with the current data.We estimate the mass of the black hole using the modelled inner disc temperature to be 30M· ≲ Mcosi ≲ 200M· based on a Shakura-Sunyaev disc model. Through a study of the hardness and high-energy curvature of available X-ray observations, we find that the accretion state of X-1 is not determined by luminosity alone.

Original languageEnglish (US)
Pages (from-to)642-650
Number of pages9
JournalMonthly Notices of the Royal Astronomical Society
Issue number1
StatePublished - Jul 26 2014

All Science Journal Classification (ASJC) codes

  • Astronomy and Astrophysics
  • Space and Planetary Science


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