Bursting Neutron Stars: Spectral Formation Theory and Its Application to Massand Radius Determination

Thermonuclear burning in the matter accumulatedon the surface of an accreting neutron star isunstable under certain conditions, which leads topowerful explosions also called Type I X-raybursts. This book covers the theory ofspectral formation in the atmospheres of neutronstars during these violent events as well as itsapplication to observational data on X-ray bursts. The main goal of the presented study is a propermeasurement of the fundamental properties forneutron stars. We take bothanalytical and numerical approaches to the problem ofradiative transfer in X-ray illuminated atmosphereswhich account for all crucial physical factors suchas Comptonization, free-free absorption and emission. We apply our models to the data collected with NASA'sRossi X-ray Timing Explorer mission in order toconstrain neutron star masses and radii for fiveX-ray burster 4U 1728-34, 4U 1820-30, Cygnus X-2, EXO0748-676 and GS 1826-24. The developed neutron starmass-radius measurement method has a great potentialfor application to new and archival X-ray data. Itcan provide scientists with a vital information onvarious aspects of physics of compact objects.