We observed SAX J1808.4-3658 (1808), the first accreting millisecond pulsar, in deep quiescence with XMM-Newton and (near-simultaneously) Gemini-South. The X-ray spectrum of 1808 is similar to that observed in quiescence in 2001 and 2006, describable by an absorbed power-law with photon index 1.74 ± 0.11 and unabsorbed X-ray luminosity LX = 7.9 ± 0.7 × 10 31 ergs s, for NH = 1.3 × 10 21 cm. Fit...

We argue that the bursting, transient X-ray source GRO J1744-28 is a binary consisting of a very low-mass (M ≈ 0.2M⊙), highly evolved giant star that is transferring mass by Roche lobe overflow onto a high-mass (M ≈ 1.8M⊙) neutron star. We explore a picture in which the bursts are due to thermonuclear flashes in matter that has accreted onto the neutron star. We attribute the unusually hard spe...

Relativistic nuclear energy density functionals (RNEDF) have become a standard framework for nuclear structure studies of ground-state properties and collective excitations over the entire nuclide chart [1]. By employing recent observational constraints on the neutron star mass, a universal RNEDF has been established that simultaneously describes the properties of finite nuclei and neutron star...

We study the effect of a magnetic field on the strage quark matter and apply to strange star. We found that the strange star becomes more compact in presence of strong magnetic field. PACS NO.: 04.40.-b, 97.60.Jd, 97.60.Gb, 98.35Eg Typeset using REVTEX 1 There are several different scenarios for estimation of the magnetic field strength at the surface of neutron star. These are: theoretical mod...

The remnant of a neutron star binary coalescence is expected to be temporarily stabilised against gravitational collapse by its differential rotation. We explore the possibility of dynamo activity in this remnant and assess the potential for powering a short-duration gamma-ray burst (GRB). We analyse our three-dimensional hydrodynamic simulations of neutron star mergers with respect to the flow...

The binaries PSR J1141–6545 and PSR B2303+46 each appear to contain a white dwarf which formed before the neutron star. We describe an evolutionary pathway to produce these two systems. In this scenario, the primary transfers its envelope onto the secondary which is then the more massive of the two stars, and indeed sufficiently massive later to produce a neutron star via a supernova. The core ...

Quark phases in neutron stars and a " third family " of compact stars as a signature for phase transitions * Abstract The appearance of quark phases in the dense interior of neutron stars provides one possibility to soften the equation of state (EOS) of neutron star matter at high densities. This softening leads to more compact equilibrium configurations of neutron stars compared to pure hadron...

Neutrinos emitted from near the surface of the hot proto-neutron star produced by a supernova explosion may be subject to significant gravitational redshift at late times. Electron antineutrinos (ν̄e) decouple deeper in the gravitational potential well of the neutron star than do the electron neutrinos (νe), so that the ν̄e experience a larger redshift effect than do the νe. We show how this diff...

We present raytracing computations for light emitted from the surface of a rapidly-rotating neutron star in order to construct light curves for X-ray pulsars and bursters. These calculations are for realistic models of rapidly-rotating neutron stars which take into account both the correct exterior metric and the oblate shape of the star. We find that the most important effect arising from rota...

The accretion of ≈ 0.1 – 1 M⊙ of material by a neutron star through Roche lobe overflow of its companion or through white-dwarf/neutron-star coalescence in a low mass binary system could be enough to exceed the critical mass of a neutron star and trigger its collapse to a black hole, leading to the production of a short gamma-ray burst (SGRB). In this model, SGRBs would often be found in early-...