paper

Cooling neutron star in the Cassiopeia~A supernova remnant: Evidence for superfluidity in the core

arXiv:1012.0045 · doi:10.1111/j.1745-3933.2011.01015.x

Abstract

According to recent results of Ho & Heinke (2009) and Heinke & Ho (2010), the Cassiopeia A supernova remnant contains a young neutron star which has carbon atmosphere and shows noticeable decline of the effective surface temperature. We report a new (November 2010) Chandra observation which confirms the previously reported decline rate. The decline is naturally explained if neutrons have recently become superfluid (in triplet-state) in the NS core, producing a splash of neutrino emission due to Cooper pair formation (CPF) process that currently accelerates the cooling. This scenario puts stringent constraints on poorly known properties of NS cores: on density dependence of the temperature for the onset of neutron superfluidity [ should have a wide peak with maximum K], on the reduction factor of CPF process by collective effects in superfluid matter (), and on the intensity of neutrino emission before the onset of neutron superfluidity (30--100 times weaker than the standard modified Urca process). This is serious evidence for nucleon superfluidity in NS cores that comes from observations of cooling NSs.

6 pages, 3 figures, accepted for publication in MNRAS Letters

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