244 research outputs found
The Cooling Neutron Star in 3C 58
The upper limit of the effective surface temperature of the neutron star (NS)
PSR J0205+6449 in the supernova remnant 3C 58 obtained recently by Slane et al.
(2002) is analyzed using a modern theory of NS cooling (Kaminker et al. 2002).
The observational limit can be explained by cooling of a superfluid NS with the
core composed of neutrons, protons and electrons, where direct Urca process is
forbidden. However, combined with the data on the surface temperatures of other
isolated NSs, it gives evidence (emphasized by Slane et al.) that direct Urca
process is open in the inner cores of massive NSs. This evidence turns out to
be less stringent than the evidence provided by the well known observations of
Vela and Geminga.Comment: 3 pages, 2 figures, AA Letters (submitted
Neutrino Emission from Neutron Stars
We review the main neutrino emission mechanisms in neutron star crusts and
cores. Among them are the well-known reactions such as the electron-positron
annihilation, plasmon decay, neutrino bremsstrahlung of electrons colliding
with atomic nuclei in the crust, as well as the Urca processes and neutrino
bremsstrahlung in nucleon-nucleon collisions in the core. We emphasize recent
theoretical achievements, for instance, band structure effects in neutrino
emission due to scattering of electrons in Coulomb crystals of atomic nuclei.
We consider the standard composition of matter (neutrons, protons, electrons,
muons, hyperons) in the core, and also the case of exotic constituents such as
the pion or kaon condensates and quark matter. We discuss the reduction of the
neutrino emissivities by nucleon superfluidity, as well as the specific
neutrino emission produced by Cooper pairing of the superfluid particles. We
also analyze the effects of strong magnetic fields on some reactions, such as
the direct Urca process and the neutrino synchrotron emission of electrons. The
results are presented in the form convenient for practical use. We illustrate
the effects of various neutrino reactions on the cooling of neutron stars. In
particular, the neutrino emission in the crust is critical in setting the
initial thermal relaxation between the core and the crust. Finally, we discuss
the prospects of exploring the properties of supernuclear matter by confronting
cooling simulations with observations of the thermal radiation from isolated
neutron stars.Comment: review, 165 pages, Physics Reports, 2001 in pres
Bremsstrahlung neutrinos from electron-electron scattering in a relativistic degenerate electron plasma
We present a calculation of neutrino pair bremsstrahlung due to
electron-electron scattering in a relativistic degenerate plasma of electrons.
Proper treatment of the in-medium photon propagator, i.e., inclusion of Debye
screening of the longitudinal part and Landau damping of the transverse part,
leads to a neutrino emissivity which is several orders of magnitude larger than
when Debye screening is imposed for the tranverse part. Our results show that
this in-medium process can compete with other sources of neutrino radiation and
can, in some cases, even be the dominant neutrino emission mechanism. We also
discuss the natural extension to quark-quark bremsstrahlung in gapped and
ungapped quark matter.Comment: 15 pages, 7 figure
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