相关论文: X-ray Sources in the Dwarf Spheroidal Galaxy Draco
A previous study of the X-ray luminosity function of the X-ray sources in the field of the Draco dwarf spheroidal (dSph) galaxy indicated the presence of a population of unknown X-ray sources in the soft energy range of 0.5-2 keV. In 2015,…
We present the results of the analysis of deep archival \sat\ observations towards the dwarf spheroidal galaxies Draco, Leo I, Ursa Major II and Ursa Minor in the Milky Way neighbourhood. The X-ray source population is characterized and…
We searched for an X-ray line at energies around 3.5 keV in deep, ~1.6 Msec XMM-Newton observations of the dwarf spheroidal galaxy Draco. No line was found in either the MOS or the PN detectors. The data in this energy range are completely…
We report the results of a deep Chandra survey of the Sculptor dwarf spheroidal galaxy. We find five X-ray sources with $L_X$ of at least $6\times10^{33}$ ergs/sec with optical counterparts establishing them as members of Sculptor. These…
We present an analysis of the X-ray spectral properties of 61 hard X-ray selected (2-8 keV) sources from the bright ($f_{2-8 keV}>10^{-14}$ \funits) {\it XMM-Newton}/2dF survey. This comprises of 9 {\it XMM-Newton} pointings in the North…
ROSAT observations found no convincing evidence for X-ray sources located in local dwarf spheroidal galaxies (dSph). Now with more sensitive instruments on board Chandra and XMM-Newton we can reach fainter luminosity levels. We report on an…
We present results of a search for the 3.5 keV emission line in our recent very long (~ 1.4 Ms) XMM-Newton observation of the Draco dwarf spheroidal galaxy. The astrophysical X-ray emission from such dark matter-dominated galaxies is faint,…
We present a study of X-ray source populations in M87, the cD galaxy of the Virgo cluster, using 12 archival {\it Chandra} observations with a total exposure of $\sim$680 ks spanning about a decade. A total of 346 point-like sources are…
We present an analysis of the X-ray properties of the Magellanic-type galaxy NGC 55 based on two contiguous XMM-Newton observations. We detect a total of 137 X-ray sources in the field of view, 42 of which are located within the optical…
We present the results of the analysis of three XMM-Newton observations of the Willman 1 dwarf spheroidal galaxy (Wil 1). X-ray sources are classified on the basis of spectral analysis, hardness ratios, X-ray-to-optical flux ratio, X-ray…
We analysed observations with XMM-Newton in the field of the Sculptor dwarf spheroidal galaxy (dSph). The aim of the study was the classification of X-ray binaries and accreting white dwarfs, which belong to the Sculptor dSph. Using…
We investigated the X-ray spectral properties of a collection of low-mass X-ray binaries (LMXBs) within a sample of 15 nearby early-type galaxies observed with Chandra. We find that the spectrum of the sum of the sources in a given galaxy…
In this paper we investigate the X-ray spectra and X-ray spectral variability of compact X-ray sources for 3 Chandra observations of the Local Group galaxy M33. The observations are centered on the nucleus and the star forming region NGC…
X-ray point sources in galaxies are dominated by X-ray binaries (XRBs) that are variables or transients and whether their variability would alter the X-ray luminosity functions (XLF) is still in debate. Here we report on NGC 7331 as an…
We present the first results of an XMM-Newton EPIC observation of the luminous X-ray source population in the supergiant spiral galaxy M101. We have studied the properties of the fourteen most luminous sources, all of which have intrinsic…
We present a sample of hard X-ray selected candidate black holes (BHs) in 19 dwarf galaxies. BH candidates are identified by cross-matching a parent sample of ~44,000 local dwarf galaxies (M_stellar < 3 x 10^9 Msun, z<0.055) with the…
The nearby dwarf spheroidal galaxy Draco with its high mass to light ratio is one of the most auspicious targets for indirect dark matter searches. Annihilation of hypothetical DM particles can result in high-energy gamma-rays, e.g. from…
We present the results of a systematic analysis of the XMM-Newton spectra of nearby optically bright QSOs. The objects have been selected from X-ray Galaxy Catalog Xgal20. It is a catalog of 1172 manually identified and classified galaxies,…
Summary of abstract: The existence of a new population of yet unrecognized x-ray sources has been often suggested to resolve some pecularities in the properties of the x-ray background (XRB), and has recently been indicated by an analysis…
We present a comprehensive X-ray point source catalog of NGC 404 obtained as part of the Chandra Local Volume Survey. A new, 97 ks Chandra ACIS-S observation of NGC 404 was combined with archival observations for a total exposure of ~123…