I discuss the nature of the compact X-ray source inside the supernova remnant RCW 103. Several models, based on the accretion onto a compact object such as a neutron star or a black hole (isolated or binary), are analyzed. I show that it is more likely that the X-ray source is an accreting neutron star than an accreting black hole. I also argue that models of a binary system with an old accreti...

(Received February 1, 2008) As pointed out by Kutschera and Wójcik, very low concentration of protons combined with a specific density dependence of effective neutron– proton interaction could lead to a localization of “proton impurities” in neutron medium at densities exceeding four times normal nuclear matter density. We study consequences of the localization of protons for transport processe...

1550-7998=20 Numerical simulations of binary neutron stars by Wilson, Mathews, and Marronetti indicated that neutron stars that are stable in isolation can be made to collapse to black holes when placed in a binary. This claim was surprising as it ran counter to the Newtonian expectation that a neutron star in a binary should be more stable, not less. After correcting an error found by Flanagan...

The detections of gravitational waves (GWs) from binary neutron star (BNS) systems and star--black hole (NSBH) provide new insights into dense matter properties in extreme conditions associated high-energy astrophysical processes. However, currently information about NS equation state (EoS) is extracted with very limited precision. Meanwhile, the fruitful results serendipitous discovery $\gamma...

Combining resolved spectroscopy with deep imaging, XMM-Newton is providing new insights on the particle acceleration processes long known to be at work in the magnetospheres of isolated neutron stars. According to a standard theoretical interpretation, in neutron stars' magnetospheres particles are accelerated along the B field lines and, depending on their charge, they can either move outward,...

After giving an overview of the history and idea of neutron stars, I shall discuss, in part one of my lectures, the physics of dense neutron star matter. In this connection concepts like chemical equilibrium and electric charge neutrality will be outlined, and the baryonic and mesonic degrees of freedom of neutron star matter as well as the transition of confined hadronic matter into quark matt...

Two broad absorption features were discovered in the Chandra/ACIS spectrum of the isolated neutron star 1E1207.4-5209 (Sanwal et al. 2002). Expanding on our previous paper (Hailey & Mori 2002), we describe the atomic physics methodology which leads to the identification of this neutron star’s atmospheric composition. The solution of Schrödinger’s equation in an intense magnetic field combined w...

Properties of non-rotating and rapidly rotating protoneutron stars and neutron stars are investigated. Protoneutron stars are hot, lepton rich neutron stars which are formed in TypeII supernovae. The hot dense matter is described by a realistic equation of state which is obtained by extending a recent approach of Myers and Świa̧tecki to the nuclear mass formula. We investigate the properties of ...

We suggest that the unique X-ray source 1E161348-5055 at the centre of the supernova remnant RCW 103 consists of a neutron star in close orbit with a low mass main sequence star. The time signature of 6.67 hr is interpreted as the neutron star’s spin period. This requires the neutron star to be endowed with a high surface magnetic field of ∼ 10 G. Magnetic or/and material (propeller) torques ar...

We review recent progress in understanding the hydrodynamics of compact binary mergers using relativistic smoothed particle hydrodynamics (SPH) codes. Recent results are discussed for both double neutron stars and black hole – neutron star binaries. The gravitational wave signals from these mergers contain a lot of information about the masses and radii of the stars and the equation of state of...