We combine the idea of movement of magnetic flux tubes in the stellar interiors with the analysis of crustal physics of accreting neutron stars in lowand high-mass X-ray binaries to explain the bimodal magnetic field distribution of binary pulsars. We propose that this distribution may result from different crustal properties of neutron stars with different accretion rates and amounts of accret...

We suggest that a neutron star with a strong magnetic field, spiraling into the envelope of a companion star, can generate a “companion induced SN-like off-center explosion”. The strongly magnetized neutron star (“magnetar”) is born in a supernova explosion before entering into an expanding envelope of a supergiant companion. If the neutron star collapses into a black hole via the hypercritical...

Gravitational radiation (GR) drives an instability in certain modes of rotating stars. This instability is strong enough in the case of the r-modes to cause their amplitudes to grow on a timescale of tens of seconds in rapidly rotating neutron stars. GR emitted by these modes removes angular momentum from the star at a rate which would spin it down to a relatively small angular velocity within ...

I give a brief introduction to the problem of detecting gravitational radiation from neutron stars. After a review of the mechanisms by which such stars may produce radiation, I consider the different search strategies appropriate to the different kinds of sources: isolated known pulsars, neutron stars in binaries, and unseen neutron stars. The problem of an all-sky survey for unseen stars is t...

Estimates from the current pulsar birth rate and the number of supernovae to account for the heavy-element abundance suggest that in total 10 to 10 isolated neutron stars exist in our Galaxy. Only a small fraction is detectable as young neutron stars due to their emission of thermal X-rays (for ∼10 years) or pulsed radio emission (for ∼10 years). Proposals that an old ”recycled” population of i...

Thermal X-ray radiation from neutron star soft X-ray transients in quiescence provides the strongest constraints on the cooling rates of neutron stars, and thus on the interior composition and properties of matter in the cores of neutron stars. We analyze new (2006) and archival (2001) XMM-Newton observations of the accreting millisecond pulsar SAX J1808.4–3658 in quiescence, which provide the ...

We present a model for the anomalous X-ray pulsars (AXPs) in which the emission is powered by accretion from a fossil disk, established from matter falling back onto the neutron star following its birth. The time-dependent accretion drives the neutron star towards a “tracking” solution in which the rotation period of the star increases slowly, in tandem with the declining accretion rate. For ap...

Rapid uniform rotation of newborn neutron stars (protoneutron stars) is studied for a range of internal temperatures and entropies per baryon predicted by the existing numerical simulations. Calculations are performed using general relativistic equations of hydrostatic equilibrium of rotating, axially symmetric stars. Stability of rotating configurations with respect to mass shedding and the ax...

Observation of cooling neutron stars can potentially provide information about the states of matter at supernuclear densities. We review physical properties important for cooling such as neutrino emission processes and superfluidity in the stellar interior, surface envelopes of light elements due to accretion of matter and strong surface magnetic fields. The neutrino processes include the modif...

The interpretation of Fourier spectra in the time domain is critically examined. Power density spectra defined and calculated in the time domain are compared with Fourier spectra in the frequency domain for three different types of variability: periodic signals, Markov processes and random shots. The power density spectra for a sample of neutron stars and black hole binaries are analyzed in bot...