Related papers: Energy Feedback from X-ray Binaries in the Early U…
The Chandra Deep Field-South and North surveys (CDFs) provide unique windows into the cosmic history of X-ray emission from normal (non-active) galaxies. Scaling relations of normal galaxy X-ray luminosity (L_X) with star formation rate…
The features and make up of the population of X-ray sources in Galactic star clusters reflect the properties of the underlying stellar environment. Cluster age, mass, stellar encounter rate, binary frequency, metallicity, and maybe other…
Understanding of the role of X-rays for driving the thermal evolution of the intergalactic medium (IGM) at high redshifts is one of important questions in astrophysics. High-mass X-ray binaries (HMXBs) in early stellar populations are prime…
The extragalactic gamma-ray sky is dominated by two classes of sources: Gamma-Ray Bursts (GRBs) and radio loud active galactic nuclei whose jets are pointing at us (blazars). We believe that the radiation we receive from them originates…
We investigate the dependence of the low-mass X-ray binary (LMXB) population in early-type galaxies on stellar age, by selecting 20 massive nearby early-type galaxies from the Chandra archive occupying a relatively narrow range of masses…
Inspired by the excess soft X-ray emission recently detected in Green Pea galaxies, we model the soft X-ray emission (0.5 - 2.0 keV) of hot gas from star cluster winds. By combining individual star clusters, we estimate the soft X-ray…
By now there is substantial evidence that Gamma-Ray Bursts (GRBs) originate at cosmological distances from very powerful explosions. The interaction between a GRB and its surrounding environment has dramatic consequences on the environment…
X-ray binaries may have helped reionize the early Universe by enabling Lyman continuum escape. We analyzed a set of 8 local galaxies that are potential Lyman leaking galaxies, identified by a blue color and weak emission lines, using…
X-ray spectroscopy offers an opportunity to study the complex mixture of emitting and absorbing components in the circumnuclear regions of active galactic nuclei, and to learn about the accretion process that fuels AGN and the feedback of…
The X-ray luminosity function (XLF) of galaxies is dominated by AGN (classified by their optical spectra) above Lx=10**42 erg/s, below this value by normal galaxies. The X-ray flux of AGN at low X-ray luminosity therefore contains…
X-ray binaries, powered by black holes, neutron stars, or white dwarfs accreting matter from a companion star, are among the brightest beacons in galaxies, outshining the Sun by a factor of millions. Most emit primarily above 0.3 keV in…
We present the first comprehensive search for high-energy neutrino emission from high- and low-mass X-ray binaries conducted by IceCube. Galactic X-ray binaries are long-standing candidates for the source of Galactic hadronic cosmic rays…
Using a sample of two hundred luminous (L_unabs>10^38 erg/s, where L_unabs is the unabsorbed 0.25-8 keV luminosity) high-mass X-ray binary (HMXB) candidates found with Chandra in 27 nearby galaxies, we have constructed the collective X-ray…
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…
We present an X-ray stacking analysis of $\sim$75,000 star-forming galaxies between $0.1<z<5.0$ using the Chandra COSMOS Legacy survey to study the X-ray emission of low-luminosity active galactic nuclei (AGN) and its connection to host…
The $\gamma$-ray emission from active galactic nuclei (AGN), including both beamed blazars and misaligned-AGN, dominates the extragalactic $\gamma$-ray point-source population count and flux. While multi-wavelength studies have detected an…
The cosmic X-ray background (CXB), which peaks at an energy of ~30 keV, is produced primarily by emission from accreting supermassive black holes (SMBHs). The CXB therefore serves as a constraint on the integrated SMBH growth in the…
Several models for the hard X-ray Background (XRB) suggest that it is due to the emission from heavily obscured AGN. Recent studies have revealed the presence of a new population of hard X-ray sources which must contribute significantly to…
In order to help understand the phenomena of X-ray emission from early-type galaxies, we obtained an optically flux-limited sample of 34 early-type galaxies, observed with ROSAT. A previous analysis of this sample suggested that the most…
We present a set of controlled hydrodynamical simulations to study the effects of strong galactic outflows on the density and temperature structures, and associated X-ray signatures, of extra-planar and circumgalactic gas. We consider three…