Related papers: X-ray sources in Galactic old open star clusters

We use simple energetic arguments to estimate the contribution of massive X-ray binaries and supernova remnants to the cosmic X-ray background (XRB) at energies in excess of 2 keV. Recent surveys have shown that AGN probably account for…

We present a new edition of the catalogue of high-mass X-ray binaries in the Galaxy. The catalogue contains source name(s), coordinates, finding chart, X-ray luminosity, system parameters, and stellar parameters of the components and other…

We present the results of the optical identifications of a set of X-ray sources from the all-sky surveys of INTEGRAL and SWIFT observatories. Optical data were obtained with Russian-Turkish 1.5-m Telescope (RTT150). Nine X-ray sources were…

General Relativity predicts that binary systems of stars produce gravitational waves of significant intensity. Here we are particularly interested in the cataclysmic variable binaries (CVs). These systems emit low frequency gravitational…

Massive Star Clusters (SCs) have been proposed as additional contributors to Galactic Cosmic rays (CRs), to overcome the limitations of supernova remnants (SNRs) to reach the highest energy end of the CR spectrum. Thanks to fast mass losses…

We analyse a Chandra observation of the rich globular cluster NGC 362, finding 33 X-ray sources within 1' (1.2 half-mass radii) of the cluster center. Spectral analysis of the brightest source (X1) shows blackbody-like emission, indicating…

Building upon three late-type galaxies in the Virgo cluster with both a predicted black hole mass of less than $\sim$10$^5$ M$_{\odot}$ and a centrally-located X-ray point-source, we reveal 11 more such galaxies, more than tripling the…

Cataclysmic variables (CVs) are binary systems with a white dwarf accreting matter from a low-mass star, making them significant sources of X-ray emission in the Galaxy. We present a systematic search for X-ray emitting CV candidates by…

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…

I analyze 101 observations from the ROSAT archive to search for X-ray sources in or near 55 globular clusters. New sources are found in the cores of NGC362 (a double source), NGC6121 (marginally significant), NGC6139, and NGC6266; and…

We present the results of a Chandra/HST study of the point sources of the NGC 4472. We identify 144 X-ray sources, 72 with HST matches. The optical data show 1102 sources, 829 with globular cluster colors. Thirty matches are found - likely…

Using new Chandra X-ray observations and existing XMM-Newton X-ray and Hubble far ultraviolet observations, we aim to detect and identify the faint X-ray sources belonging to the Galactic globular cluster NGC 2808 in order to understand…

We identify 69 X-ray sources discovered by the Galactic Bulge Survey (GBS) that are coincident with, or very close to bright stars in the Tycho-2 catalog. Additionally, two other GBS sources are resolved binary companions to Tycho-2 stars…

Gravitational lensing by clusters of galaxies affects the cosmic X-ray background (XRB) by altering the observed density and flux distribution of background X-ray sources. At faint detection flux thresholds, the resolved X-ray sources…

(abridged) Hard X-ray surveys performed by the INTEGRAL satellite have discovered a conspicuous fraction (up to 30%) of unidentified objects among the detected sources. Here we continue our identification program by selecting probable…

Population studies of EGRET gamma-ray sources indicate that there is a distinctive population of bright sources at low galactic latitudes. The sources have a distribution consistent with that of young galactic objects, with a concentration…

We have obtained high resolution (<1") deep x-ray images of the globular cluster 47Tucanae (NGC 104) with the Chandra X-ray Observatory to study the population of compact binaries in the high stellar density core. A 70 kilosec exposure of…

We have incorporated the description of the X-ray properties of Active Galactic Nuclei (AGNs) into a semi-analytic model of galaxy formation, adopting physically motivated scaling laws for accretion triggered by galaxy encounters. Our model…

In this paper we consider a large sample of optically selected clusters, in order to elucidate the physical reasons for the existence of X-ray underluminous clusters. For this purpose we analyze the correlations of the X-ray and optical…

Open clusters are thought to be the birth place of most stars in the Galaxy. Thus, they are excellent laboratories for investigating stellar evolution, and X-ray properties of various types of stars (including binary stars, evolved stars,…