TY - JOUR
T1 - Radiative processes, spectral states and variability of black-hole binaries
AU - Zdziarski, Andrzej A.
AU - Gierliński, Marek
PY - 2004/5/1
Y1 - 2004/5/1
N2 - We review radiative processes responsible for X-ray emission in hard (low) and soft (high) spectral states of black-hole binaries. The main process in the hard state appears to be scattering of blackbody photons from a cold disk by thermal electrons in a hot inner flow, and any contribution from nonthermal synchrotron emission is at most small. In the soft states, blackbody disk emission dominates energetically, and its high-energy tail is due to scattering by hybrid, thermal/nonthermal electrons, probably in active regions above the disk surface. State transitions appear to correspond to a variable inner radius of the cold disk driven by changes of the accretion rate. The existence of two accretion solutions, hot and cold, in a range of the accretion rate leads to hysteresis in low-mass X-ray binaries.
AB - We review radiative processes responsible for X-ray emission in hard (low) and soft (high) spectral states of black-hole binaries. The main process in the hard state appears to be scattering of blackbody photons from a cold disk by thermal electrons in a hot inner flow, and any contribution from nonthermal synchrotron emission is at most small. In the soft states, blackbody disk emission dominates energetically, and its high-energy tail is due to scattering by hybrid, thermal/nonthermal electrons, probably in active regions above the disk surface. State transitions appear to correspond to a variable inner radius of the cold disk driven by changes of the accretion rate. The existence of two accretion solutions, hot and cold, in a range of the accretion rate leads to hysteresis in low-mass X-ray binaries.
UR - http://www.scopus.com/inward/record.url?scp=11044236543&partnerID=8YFLogxK
U2 - 10.1143/PTPS.155.99
DO - 10.1143/PTPS.155.99
M3 - Review article
AN - SCOPUS:11044236543
VL - 155
SP - 99
EP - 119
JO - Progress of Theoretical Physics Supplements
JF - Progress of Theoretical Physics Supplements
SN - 0375-9687
ER -