Related papers: X-ray emissivity of old stellar populations: a loc…
Chandra observations of the X-ray faint elliptical galaxy NGC 4697 resolve much of the X-ray emission (61% within one effective radius) into ~80 point sources, of which most are low mass X-ray binaries (LMXBs). These LMXBs provide the bulk…
The high energy X-ray and ultraviolet (UV) radiation fields of exoplanet host stars play a crucial role in controlling the atmospheric conditions and the potential habitability of exoplanets. Major surveys of the X-ray/UV emissions from…
We have derived the X-ray luminosities of a sample of galaxies in groups, making careful allowance for contaminating intragroup emission. The L_X:L_B and L_X:L_{FIR} relations of spiral galaxies in groups appear to be indistinguishable from…
The diffuse Fe XXV (6.7 keV) line emission observed in the Galactic ridge is widely accepted to be produced by a superposition of a large number of unresolved X-ray point sources. In the very central degrees of our Galaxy, however, the…
X-ray emitting gaseous halos, such as that in elliptical galaxies like NGC 4472, cannot have been produced solely from gas expelled from galactic stars. In traditional models for the evolution of hot interstellar gas (cooling flows) in…
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…
Luminous elliptical galaxies generally display a rich star cluster system, whose properties provide strong constraints on the physics of galaxy formation and evolution. Star cluster system studies, however, concentrate on galaxies located…
NGC 253 is a local, star-bursting spiral galaxy with strong X-ray emission from hot gas, as well as many point sources. We have conducted a spectral survey of the X-ray population of NGC 253 using a deep XMM-Newton observation.NGC 253 only…
I review the current status of studies of the X-ray sources in Galactic old open clusters. Cataclysmic variables (CVs), magnetically-active binaries (ABs), and sub-subgiants (SSGs) dominate the X-ray emission of old open clusters.…
We present theoretical models for the formation and evolution of populations of low-mass X-ray binaries (LMXB) in the two elliptical galaxies NGC 3379 and NGC 4278. The models are calculated with the recently updated StarTrack code…
Previous studies suggest that the Galactic diffuse X-ray emission is composed of unresolved point sources, primarily mCVs. However, nearby mCVs have a much lower 6.7 keV line equivalent width ($\rm EW_{6.7}$) compared to the diffuse X-ray…
We present three-integral dynamical models for the three Local Group dwarf elliptical galaxies: NGC147, NGC185, and NGC205. It is the first time models are constructed for the Local Group dEs that allow for the presence of dark matter at…
The slow inward flow of the hot gas in elliptical galaxy cooling flows is nearly impossible to detect directly due to instrumental limitations. However, in rotating galaxies, if the inflowing gas conserves angular momentum, it will…
The population-wide properties and demographics of extragalactic X-ray binaries (XRBs) correlate with the star formation rates (SFRs), stellar masses ($M_{\star}$), and environmental factors (such as metallicity, $Z$) of their host galaxy.…
The thermodynamics of the diffuse, X-ray emitting gas in clusters of galaxies is determined by gravitational processes associated with shock heating, adiabatic compression, and non-gravitational processes such as heating by SNe, stellar…
The Milky Way centre exhibits an intense flux in the gamma and X-ray bands, whose origin is partly ascribed to the possible presence of a large population of millisecond pulsars (MSPs) and cataclysmic variables (CVs), respectively. However,…
The discovery of hard, power-law X-ray emission from a sample of six nearby elliptical galaxies, including the dominant galaxies of the Virgo,Fornax and Centaurus clusters (M87, NGC 1399 and NGC 4696, respectively), and NGC 4472, 4636 and…
We obtain total galaxy X-ray luminosities, $L_X$, originating from individually detected point sources in a sample of 47 galaxies in 15 compact groups of galaxies (CGs). For the great majority of our galaxies, we find that the detected…
By studying Swift X-ray spectra of an optically-selected, non-magnetic sample of nearby cataclysmic variables (CVs), we show that there is a population with X-ray luminosity much lower than accounted for in existing studies. We find an…
Elliptical galaxies comprise primarily old stars, which collectively generate a long-lasting feedback via stellar mass-loss and Type Ia SNe. This feedback can be traced by X-ray-emitting hot gas in and around such galaxies, in which little…