By means of two-dimensional (2D) simulations we study hydrodynamic instabilities during the first seconds of neutrino-driven supernova explosions. We use a PPM hydrodynamics code, supplemented with an approximative, gray, nonequilibrium treatment of radial neutrino transport, based on an analytic integration of the neutrino number and energy equations. Tests show that this treatment reproduces ...

We argue that significant probability of protons with momenta above their Fermi surface leads for proton concentrations p/n ≥ 1/8 to the enhancement of termally excited direct and modified URCA processes within a cold neutron star, and to a nonzero probability of direct URCA processes for small proton concentrations (p/n ≤ 1/8). We evaluate high momentum tails of neutron, proton and electrons d...

The EOS of strongly interacting matter at densities ten to fifteen orders of magnitude larger than the typical density of terrestrial macroscopic objects determines a number of neutron star properties, including the pattern of gravitational waves emitted following the excitation of nonradial oscillation modes. This paper reviews some of the approaches employed to model neutron star matter, as w...

We have investigated the relation of the direction of the momentum among the matter, neutrino, and proto-neutron star in a collapse-driven supernova in order to discuss the pulsar kick. In particular, we have investigated the effects of the pulsar motion on the explosion, which are neglected in the previous study. As a result, we have concluded that the direction of the total momentum of the ma...

Recent observations of 1E 161348-5055 the neutron-star candidate at the center of the supernova remnant RCW 103, show that a component of its emission varies sinusoidally with a period of approximately six hours. We argue that this period is what one would expect for a freely precessing neutron star with a spin period of about one second. We produce light curves for a freely precessing neutron ...

Cen X-4 is one of the best studied low-mass neutron star transients in quiescence. Thanks to XMM-Newton large throughput, Cen X-4 was observed at the highest signal to noise ever. This allowed us to disclose rapid (> 100 s), large (45 ± 7 rms in the 10 −4 − 1 Hz range) intensity variability, especially at low energies. In order to highlight the cause of this variability, we divided the data int...

Observations of Type I X-ray bursts have long been taken as evidence that the sources are neutron stars. Black body models approximate the spectral data and imply a suddenly heated neutron star cooling over characteristic times of seconds to minutes. The phenomena are convincingly explained in terms of nuclear burning of accreted gas on neutron stars with low mass companion stars. Prospects are...

After a brief summary of neutron star cooling theory I present results which emphasize the importance of baryon pairing in the neutron star core. I show how the thermal evolution may be totally controlled by pairing for models which include only nucleons and models containing also hyperons. Finally, I consider the thermal evolution of ultramagnetized neutron stars whose existence has been infer...