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arXiv · 1008.0558

Fast variability as a tracer of accretion regimes in black hole transients

T. Muñoz-Darias·S. Motta·T. M. Belloni
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Abstract

We present the rms-intensity diagram for black hole transients. Using observations taken with the Rossi X-ray timing explorer we study the relation between the root mean square (rms) amplitude of the variability and the net count-rate during the 2002, 2004 and 2007 outbursts of the black hole X-ray binary GX 339-4. We find that the rms-flux relation previously observed during the hard state in X-ray binaries does not hold for the other states, when different relations apply. These relations can be used as a good tracer of the different accretion regimes. We identify the hard, soft and intermediate states in the rms-intensity diagram. Transitions between the different states are seen to produce marked changes in the rms-flux relation. We find that one single component is required to explain the ~ 40 per cent variability observed at low count rates, whereas no or very low variability is associated to the accretion-disc thermal component.

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T. Muñoz-Darias, S. Motta, T. M. Belloni. 2010-08-03. Fast variability as a tracer of accretion regimes in black hole transients. https://doi.org/10.1111/j.1365-2966.2010.17476.x

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