Black-hole states in external galaxies

✍ Scribed by T.M. Belloni

• Publisher: John Wiley and Sons
• Year: 2011
• Tongue: English
• Weight: 328 KB
• Volume: 332
• Category: Article
• ISSN: 0004-6337
• DOI: 10.1002/asna.201011492

✦ Synopsis

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 (© 2011 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)