Related papers: Faint galaxies and the X-ray background
Across the Galactic disk lies a diverse population of X-ray sources, with the fainter end remaining poorly understood due to past survey sensitivity limits. We aim to classify and characterize faint X-ray sources detected in the eROSITA…
The X-ray background is generated by various classes of objects and variety of emission mechanisms. Relative contribution of individual components depends on energy. The goal is to assess the integral emission of the major components of the…
Elliptical galaxies are generally luminous sources of X-ray radiation, and contain large amounts of hot, interstellar gas. In the brighter X-ray galaxies, the inferred masses of hot gas are consistent with those expected given the present…
We present multiwaveband photometric and optical spectropolarimetric observations of the R=15.9 narrow emission line galaxy R117_A which lies on the edge of the error circle of the ROSAT X-ray source R117 (from McHardy et al 1998). The…
ROSAT deep and shallow surveys have provided an almost complete inventory of the constituents of the soft X-ray background which led to a population synthesis model for the whole X-ray background with interesting cosmological consequences.…
We present a synthesis model of the X-ray background based on the cross-correlation between mid-infrared and X-ray surveys, where the distribution of type 2 sources is assumed to follow that of luminous infrared galaxies while type 1…
In this paper we report on the analysis of a deep ROSAT HRI image of the moderately-rich cluster, Abell 2634, by which we have been able to detect the X-ray emission from the galaxies in the cluster. The ICM of Abell 2634 is an order of…
We present an estimate of the local X-ray luminosity function and emissivity for different subsamples of galaxies namely Seyferts, LINERS, star-forming and passive (no-emission-line) galaxies. This is performed by convolving their optical…
Contribution to the gamma-ray background (GRB) by galaxies bright in the far-IR (FIR) is discussed. Using observational correlations between the FIR and synchrotron emission in radio wavelengths, it is shown that the concentration of cosmic…
Today's sensitive, high-resolution X-ray observations allow the study of populations of X-ray sources, in the luminosity range of Galactic X-ray binaries, in galaxies as distant as 20-30 Mpc. The traditional astronomical tools of…
The deep X-ray surveys performed by the two major X-ray observatories on flight, Chandra and XMM, are being resolving the bulk of the cosmic X-ray background (XRB) in the 2-10 keV energy band, where the sky flux is dominated 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…
We have identified a population of blank field sources (or `blanks') among the ROSAT bright unidentified X-ray sources with faint optical counterparts. The extreme X-ray over optical flux ratio of blanks is not compatible with the main…
We use archival Chandra X-ray Observatory data to investigate X-ray emission from early-type galaxies in the rich z=0.06 cluster Abell 3128. By combining the X-ray count-rates from an input list of optically-selected galaxies, we obtain a…
We present a catalogue of 147 serendipitous X-ray sources selected to have hard spectra (alpha < 0.5) from a survey of 188 ROSAT fields. Such sources must be the dominant contributors to the X-ray background at faint fluxes. We have used…
We present deep K-band imaging at the positions of four very faint X-ray sources found in the UK ROSAT Deep Survey to have no optical counterpart brighter than R~23. Likely identifications are found within the ROSAT error circle in all four…
Recent X-ray surveys by {\it Chandra} and {\it XMM-Newton} have revealed a population of X-ray bright, optically normal galaxies (XBONGs) at moderate redshifts. We propose that many XBONGs are powered by an inner radiatively inefficient…
Presence of the apparently extended hard (2-10 keV) X-ray emission along the Galactic plane has been known since the early 1980s. With a deep X-ray exposure using the Chandra X-ray Observatory of a slightly off-plane region in the Galactic…
We present the results of the deepest optically identified X-ray survey yet made. The X-ray survey was made with the ROSAT PSPC and reaches a flux limit of 1.6x10^-15 erg cm^-2 s^-1 (0.5--2.0 keV). Above a flux limit of 2x10^-15 erg cm^-2…
The X-ray emission from the faintest X-ray elliptical and S0 galaxies is characterized by a hard ~5 keV component, and a very soft ~0.2 keV component. The hard component has generally been regarded as the integrated emission from low mass…