ROSAT HRI observations of the Crab pulsar: an improved temperature upper limit for PSR 0531+21

摘要

ROSAT HRI observations have been used to determine an upper limit of the Crab pulsar surface temperature from the off-pulse count rate. For a neutron star mass of 1.4 \Mo and a radius of 10 km as well as the standard distance and interstellar column density, the redshifted temperature upper limit is\/ T_s^\infty \le 1.55\times 10^6 K (3\sigma). This is the lowest temperature upper limit obtained for the Crab pulsar so far. Slightly different values for T_s^\infty are computed for the various neutron star models available in the literature, reflecting the difference in the equation of state.