Thermal Spectrum and Neutrino Cooling Rate of the Vela Pulsar

We reanalyse the X-ray spectrum of the PSR B0833-45 (the Vela pulsar) using the data of the Chandra space observatory. In contrast to previous works, we consider a wide range of possible masses and radii of the pulsar. The derived surface temperature of the star T-s(infinity) = 0.66(-0.01)(+0.04) MK (1 sigma level over the entire mass and radius range of our study) is consistent with earlier results. However, the preferable values of Vela's mass and radius given by the spectral analysis are different from those used previously; they are consistent with modern equation of state models of neutron star matter. In addition, we evaluate the Vela's surface temperature as a function of assumed values of its mass and radius. This allows us to analyse the neutrino cooling rates consistent with the evaluated surface temperatures and explore the additional restrictions that could be set on the Vela's mass and radius using different versions of the neutron star cooling theory.