Abstract
We present a unified treatment of the continuum radiative transfer in optically thick hot plasmas where incoherent Compton scattering is important, either in the presence or absence of strong magnetic fields, as occurs in X-ray emitting neutron stars. Numerical solutions of the transfer equations are obtained and compared to a simplified analytical treatment, including the effect of stimulated scattering in an approximate manner. The latter effect is essential in order to obtain the correct spectrum at frequencies ω ≪ kT. In field-free plasmas the Comptonization drastically changes the outgoing spectrum if ( Ne 1022 cm-3) 1 2(kT/10 keV)- 9 4 ≪ 10, where Ne and T are the electron density and temperature of the plasma. In strongly magnetized plasmas (ωB≫kT, where ωB is the cyclotron frequency) the Comptonization effects are less significant than the magnetic effects at frequencies ω ≪ ωB, for parameters typical of accreting pulsars. The Comptonization is significant only for the ordinary polarization mode, which is much less intense than the extraordinary polarization mode. On the contrary, the Comptonization changes essentially all the properties of the radiation escaping at frequencies close to the cyclotron resonance, ω {reversed tilde equals} ωB. These results are useful in the optically thick regions of neutron star models of gamma ray bursters, and are of major relevance for an appropriate treatment of models of accreting pulsars and X-ray bursters.
Original language | English (US) |
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Pages (from-to) | 187-210 |
Number of pages | 24 |
Journal | Physics Reports |
Volume | 182 |
Issue number | 3 |
DOIs | |
State | Published - Oct 1989 |
All Science Journal Classification (ASJC) codes
- General Physics and Astronomy