Related papers: Old Isolated Accreting Neutron Stars: The Diffuse …
We explore the possibility that neutron stars accreting from the winds of main-sequence stellar companions account for a significant fraction of low-luminosity, hard X-ray sources (L_X <~ 10^35 ergs/s; 1-10 keV) in the Galaxy. This work was…
The spectral properties of X--ray radiation produced in a static atmosphere around a neutron star accreting at very low rates are investigated. Previous results by Alme \& Wilson (1973) are extended to the range $10^{-7}\leq L/L_{Edd}\leq…
As many as $10^9$ neutron stars populate the Galaxy, but only $\approx 10^3$ are directly observed as pulsars or as accreting sources in X-ray binaries. In principle also the accretion of the interstellar medium may make isolated neutron…
The origin of the X-ray emission from the central region of the Galaxy has remained a mystery, despite extensive study over the past two decades. A fundamental question is the relative contribution of the point-source and diffuse components…
Accretion onto old, isolated neutron stars is reviewed. The detection of their X--ray emission with ROSAT is discussed and a summary of the current status of observations is presented.
The issue of the observability of Old Isolated Neutron Stars (ONSs) accreting from the interstellar gas, is reconsidered using the spectra presented in Zampieri {\it et al.\/} (1995). In particular, we focus our attention on the overall…
Accretion of interstellar material by an isolated neutron star is discussed. The point I address here is the interaction between the accretion flow and the stellar magnetosphere. I show that the interchange instabilities of the…
Interstellar matter that is accreted onto isolated magnetic neutron stars in the Galaxy ($\sim 10^9$ by number) is accelerated and reflected back by MHD shocks, which envelope the stars. The integrated power in the Galaxy $L_{cr,ns}$ is $…
Estimates indicate there may be $\simgreat 10^3$ low luminosity X-ray pulsars ($L \simless 10^{34} \rom{erg\;s^{-1}}$) in the Galaxy undergoing ``low-state'' wind accretion in Be/X-ray binary systems, and $\sim 10^8-10^9$ isolated neutron…
The origin of the Galactic center diffuse X-ray emission (GCDX) is still under intense investigation. We have found a clear excess in a longitudinal GCDX profile over a stellar number density profile in the nuclear bulge region, suggesting…
We model Galactic populations of accreting and cooling isolated neutron stars in the attempt to explore their link with a new class of dim soft X-ray sources revealed by ROSAT. For accretors we follow the magneto-rotational and dynamical…
Galactic X-ray emission is a manifestation of various high-energy phenomena and processes. The brightest X-ray sources are typically accretion-powered objects: active galactic nuclei and low- or high-mass X-ray binaries. Such objects with…
We exploit XMM-Newton archival data in a study of the extended X-ray emission emanating from the Galactic Centre (GC) region. EPIC-pn and EPIC-MOS observations, with a total exposure approaching 0.5 and 1 Ms respectively, were used to…
Accretion of interstellar material by a magnetized, slowly rotating isolated neutron star is discussed. We show that the average persistent X-ray luminosity of these objects is unlikely to exceed 4x10^26 erg/s. They can also appear as X-ray…
The recent discovery of a milli-second radio pulsar experiencing an accretion outburst similar to those seen in low mass X-ray binaries, has opened up a new opportunity to investigate the evolutionary link between these two different…
In this chapter we give an overview of the properties of X-ray binary systems containing a weakly magnetized neutron star. These are old (Giga-years life-time) semi-detached binary systems containing a neutron star with a relatively weak…
Accreting neutron stars in low-mass X-ray binaries show outflows -- and sometimes jets -- in the general manner of accreting black holes. However, the quantitative link between the accretion flow (traced by X-rays) and outflows and/or jets…
Accreting X-ray pulsars, located in X-ray binaries, are neutron stars with magnetic fields as strong as $B\sim10^{12\text{--}13}$ G. This review offers a concise overview of the accretion and radiation processes of X-ray pulsars and…
X-ray emission is a common feature of all varieties of isolated neutron stars (INS) and, thanks to the advent of sensitive instruments with good spectroscopic, timing, and imaging capabilities, X-ray observations have become an essential…
Dense wind of a massive star can be partially captured by a neutron star (NS) inside a compact binary system. Depending on the parameters of NS and the wind, the matter can penetrate the inner NS magnetosphere. At some distance from the NS…