THE SPECTRA OF ACCRETION DISCS IN LOW-MASS X-RAY BINARIES

We present self-consistent models for the radiative transfer in Shakur a-Sunyaev accretion discs in bright low-mass X-ray binaries (LMXBs). O ur calculations include the full effects of incoherent Compton scatter ing and the vertical temperature structure within the disc, as well as the effects of Doppler blurring and gravitational redshift. We find t hat the observed X-ray spectra are well fitted by exponentially cut-of f power-law models. The difference between the observed total spectrum and our calculated disc spectrum should reveal the spectrum of the di sc/neutron star boundary layer and other emitting regions considered t o be present in LMXBs.