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arXiv · 1012.0783

Black-hole states in external galaxies

Tomaso M. Belloni
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Abstract

A large number of Ultra-Luminous X-ray Sources in external galaxies is now known, but the discussion about their nature is still unsettled: intermediate-mass black holes or stellar-mass black holes accreting above the Eddington limit? A promising path that can provide an answer is through comparison with "normal" stellar-mass black holes. These display separate states, identified from both their energy spectra and their fast variability. Although the nature of these states and their transitions is not clear, such a comparison can be extremely useful. In this paper, I briefly outline our current phenomenological knowledge of these states and present a (partial) overview of the different approaches followed to make these comparisons.

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Tomaso M. Belloni. 2010-12-03. Black-hole states in external galaxies. https://doi.org/10.1002/asna.201011492

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