Limits on the gravitational redshift form neutron stars

The objective of the study is to investigate the range of gravitational redshifts which can be expected in the observation of emission lines originating near the surface of neutron stars. The approach used here to derive bounds on the gravitational redshifts from neutron stars is analogous to the methods developed by Hartle (1978) to derive bounds on the masses and moments of inertia for neutron stars. It is assumed that general relativity correctly describes the gravitational interaction at neutron star densities and that the stars are nonrotating, spherical, and composed of fluid matter (i.e., matter having isotropic stresses). For 1.4-solar-mass stars, the limits on the gravitational redshift are estimated at 0.854-0.184. These limits are compared with redshifts deduced from gamma-ray burst observations.