Unification of Spectral States of Accreting Black Holes
| dc.creator | Poutanen, Juri | |
| dc.creator | Coppi, Paolo | |
| dc.date | 1997-11-26 | |
| dc.date.accessioned | 2026-07-07T02:25:24Z | |
| dc.date.available | 2026-07-07T02:25:24Z | |
| dc.description | Several galactic black holes show transitions between spectral states. In this paper we present a unifying radiation transfer model that can fit the spectral data in both states. We fit individual broad-band (from 1 keV up to 4 MeV) spectral data for the "hard" and "soft" states of Cyg X-1 using an emission model where a central Comptonizing corona/cloud is illuminated by the soft photon emission from a cold disk. We assume that the energy is injected to the corona by two channels: a non-thermal one that injects energetic electrons into the coronal region, and a thermal one that heats injected and ambient electrons once they cool sufficiently to form a Maxwellian distribution, i.e., we consider a hybrid thermal/non-thermal model. Using simple scaling laws for the luminosity of the cold disk, the thermal dissipation/heating rate in the corona, and the rate of energy injection from a non-thermal source, all as functions of radius of the corona, we explain the hard-to-soft transition as the result of a decrease in the size of the corona and the inner radius of the cold disk by a factor ~ 5. For the case of Cyg X-1, we show that the bolometric luminosity of the source (mass accretion rate) does not change significantly during the transition, and thus the transition is probably the result of a disk instability. | |
| dc.description | 3 pages; 2 postscript figures; to appear in Physica Scripta in the proceedings of the Nordic Symposium "Exploiting Spectrum-X-Gamma and INTEGRAL", Copenhagen, September 14-16, 1997 | |
| dc.identifier | https://arxiv.org/abs/astro-ph/9711316 | |
| dc.identifier | http://arxiv.org/abs/astro-ph/9711316 | |
| dc.identifier | Phys.Scripta T77 (1998) 57-59 | |
| dc.identifier.uri | http://salesiana.dossiersoluciones.com/handle/123456789/11860 | |
| dc.subject | Astrophysics | |
| dc.title | Unification of Spectral States of Accreting Black Holes | |
| dc.type | text |