A new technique to measure the lifetime � of a neutron-radioactive nucleus that decays in-flight via neutron emission is presented and demonstrated utilizing MonteCarlo simulations. The method is based on the production of the neutron-unbound nucleus in a target, which at the same time slows down the produced nucleus and the residual nucleus after (multi-) neutron emission. The spectrum of the ...

γ Cassiopeia (γ Cas), is known to be a binary system consisting of a Be-type star and a low-mass (M ∼ 1M ) companion of unknown nature orbiting in the Be-disc plane. Here, we apply the quasi-spherical accretion theory on to a compact magnetized star and show that if the low-mass companion of γ Cas is a fast spinning neutron star, the key observational signatures of γ Cas are remarkably well rep...

In a cool neutron star (T . 10 K) endowed with a rather high magnetic field (B & 10 G), a phase transition may occur in the outermost layers. As a consequence the neutron star becomes “bare”, i.e. no gaseous atmosphere sits on the top of the crust. The surface of a cooling, bare neutron star does not necessarily emit a blackbody spectrum because the emissivity is strongly suppressed at energies...

We have carried out a search for radio emission from six X-ray dim isolated neutron stars (XDINSs) observed with the Robert C. Byrd Green Bank Radio Telescope (GBT) at 820 MHz. No bursty or pulsed radio emission was found down to a 4σ significance level. The corresponding flux limit is 0.01–0.04 mJy depending on the integration time for the particular source and pulse duty cycle of 2%. These ar...

We review the observational properties of transient systems made by a neutron star primary and a late dwarf companion (known also as Soft X–ray Transients) during their quiescent state. We focus on the several emission mechanisms proposed and try to compare them with observations. Finally, we review new tools to improve our comprehension of the physics of the emission processes. WHAT ARE NEUTRO...

The spectrum of neutrons emitted after the B-decay of ~Li has been measured with a large time-of-flight array. The spectrum exhibits six peaks corresponding to neutron emission from known states in the l lBe daughter nucleus. The measured branching ratios indicate significant feeding to states over a broad energy range. The energies and parities of the states are in very good agreement with the...

We present a new grid of LTE model atmospheres for weakly magnetic (B <∼ 10 10 G) neutron stars, using opacity and equation of state data from the OPAL project and employing a fully frequency and angle dependent radiation transfer. We discuss the differences to earlier models, including a comparison with a detailed NLTE calculation. As a first application of the new synthetic spectra, we re-ana...

Formation of a neutron star is accompanied by neutrino emission carring about 10% of the rest energy of the star. Toroidal field produced by twisting of a dipole field in differentially rotating star is antisymmetric. Its summation with antisymmetric toroidal field results in braking of mirror symmetry of the magnetic field . For large magnetic field the neutron decay rate depends on its streng...

Strong (B ≫ 10 G) and superstrong (B & 10 G) magnetic fields profoundly affect many thermodynamic and kinetic characteristics of dense plasmas in neutron star envelopes. In particular, they produce strongly anisotropic thermal conductivity in the neutron star crust and modify the equation of state and radiative opacities in the atmosphere, which are major ingredients of the cooling theory and s...

Hydrodynamic simulations of the merger of stellar mass black hole-neutron star binaries are compared with mergers of binary neutron stars. The simulations are Newtonian but take into account the emission and back-reaction of gravitational waves. The use of a physical nuclear equation of state allows us to include the effects of neutrino emission. For low neutron star-to-black hole mass ratios, ...