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arXiv · 1407.6254

Spectral State Transitions of the Ultraluminous X-ray Source IC 342 X-1

Hannah Marlowe·Philip Kaaret·Cornelia Lang·Hua Feng·Fabien Grise·Neal Miller·David Cseh·Stephane Corbel·Richard F. Mushotzky
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Abstract

We observed the Ultraluminous X-ray Source 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 $30~\mathrm{M_{\odot}} \lesssim M\sqrt{\mathrm{cos}i}\lesssim200~\mathrm{M_{\odot}}$ 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.

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Hannah Marlowe, Philip Kaaret, Cornelia Lang, Hua Feng, Fabien Grise, Neal Miller, David Cseh, Stephane Corbel, Richard F. Mushotzky. 2014-07-23. Spectral State Transitions of the Ultraluminous X-ray Source IC 342 X-1. https://doi.org/10.1093/mnras%2Fstu1471

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