2017/11/30 by Juri Poutanen, Alexandra Veledina, Andrzej A. Zdziarski
Physics and Astronomy · #Accretion (finance) #Accretion disc #Astronomy and Astrophysical Research #Astrophysical Phenomena and Observations #Black hole (networking) #Corona (planetary geology) #Galaxies: Formation, Evolution, Phenomena #Photon #Plasma #RADIUS #Spectral line #astro-ph.HE
paper · pdf · doi:10.1051/0004-6361/201732345
published as A&A 614, A79 (2018) · 12 pages, 8 figures; A&A, in press
openalex created_date 2017/12/04 · arxiv created 2018/03/06 · openalex publication_date 2018/03/06 · arxiv updated 2018/06/20 · openalex updated_date 2026/08/05
We study the effects of the mutual interaction of hot plasma and cold medium in black hole binaries in their hard spectral state. We consider a number of different geometries. In contrast to previous theoretical studies, we use a modern energy-conserving code for reflection and reprocessing from cold media. We show that a static corona above an accretion disc extending to the innermost stable circular orbit produces spectra not compatible with those observed. They are either too soft or require a much higher disc ionization than that observed. This conclusion confirms a number of previous findings, but disproves a recent study claiming an agreement of that model with observations. We show that the cold disc has to be truncated in order to agree with the observed spectral hardness. However, a cold disc truncated at a large radius and replaced by a hot flow produces spectra which are too hard if the only source of seed photons for Comptonization is the accretion disc. Our favourable geometry is a truncated disc coexisting with a hot plasma either overlapping with the disc or containing some cold matter within it, also including seed photons arising from cyclo-synchrotron emission of hybrid electrons, i.e. containing both thermal and non-thermal parts.