Related papers: The distribution of AGN in a large sample of galax…

Compared with numerous X-ray dominant active galactic nuclei (AGNs) without emission-line signatures in their optical spectra, the X-ray selected AGNs with optical emission lines are probably still in the high-accretion phase of black hole…

We present the X-ray spectral analysis of the 1855 extragalactic sources in the Chandra COSMOS-Legacy survey catalog having more than 30 net counts in the 0.5-7 keV band. 38% of the sources are optically classified Type 1 active galactic…

We present new Chandra X-ray Observatory and Hubble Space Telescope observations of eight optically selected broad-line AGN candidates in nearby dwarf galaxies ($z<0.055$). Including archival Chandra observations of three additional…

We present results of optical identification of the X-ray sources detected in the ASCA Large Sky Survey. Optical spectroscopic observations were done for 34 X-ray sources which were detected with the SIS in the 2-7 keV band above 3.5 sigma.…

We undertake a spectral study of a sample of bright X-ray sources taken from six XMM-Newton fields at high galactic latitudes, where AGN are the most populous class. These six fields were chosen such that the observation had an exposure…

We have surveyed 188 ROSAT PSPC fields for X-ray sources with hard spectra (alpha<0.5); such sources must be major contributors to the X-ray background at faint fluxes. In this paper we present optical identifications for 62 of these…

We analyze the X-ray properties for a sample of 23 high probability AGN candidates with ultraviolet variability identified in Wasleske et al. (2022). Using data from the Chandra X-ray Observatory and the XMM-Newton Observatory, we find…

Our goal is to probe the populations of obscured and unobscured AGN investigating their optical-IR and X-ray properties as a function of X-ray flux, luminosity and redshift within a hard X-ray selected sample of 136 X-ray sources in the XMM…

We have cross-correlated X-ray catalogs derived from archival Chandra ACIS observations with a Sloan Digital Sky Survey (SDSS) Data Release 2 (DR2) galaxy catalog to form a sample of 42 serendipitously X-ray detected galaxies over the…

We correlate the positions of 13,240 Brightest Cluster Galaxies (BCGs) with 0.1 <= z <= 0.3 from the maxBCG catalog with radio sources from the FIRST survey to study the sizes and distributions of radio AGN in galaxy clusters. We find that…

We selected a sample of sources with high X-ray over optical flux ratio from the ROSAT PSPC archives. Out of the 16 sources in our sample, one is a (possibly extreme) BL Lac and two are AGNs. Six more sources are tentatively classified as…

We cross-matched the 4XMM-DR10 catalog with the HyperLEDA database and obtained the new sample of galaxies that contain X-ray sources. Excluding duplicate observations and false matches, we present a total of 7759 galaxies with X-ray…

We present the spatial clustering properties of 1466 X-ray selected AGN compiled from the Chandra CDF-N, CDF-S, eCDF-S, COSMOS and AEGIS fields in the 0.5-8 keV band. The X-ray sources span the redshift interval 0<z<3 and have a median…

In our ongoing multi-wavelength study of cluster AGN, we find ~75% of the spectroscopically identified cluster X-ray point sources (XPS) with L(0.3-8.0keV)>10^{42} erg s^{-1} and cluster radio galaxies with P(1.4 GHz) > 3x10^{23} W Hz^{-1}…

We report the discovery of large scale structures of X-ray sources in the 1Msec observation of the Chandra Deep Field South. Two main structures appear as narrow (Delta_z < 0.02) spikes in the source redshift distribution at z=0.67 and…

We present followup optical g', r', and i', imaging and spectroscopy of serendipitous X-ray sources detected in 6 archival Chandra, images included in the Chandra, Multiwavelength Project (ChaMP). Of the 486 X-ray sources detected between…

We report the detection of a significant excess in the surface density of far-infrared sources from the Herschel-Astrophysical Terahertz Large Area Survey (H-ATLAS) within ~1 Mpc of the centres of 66 optically-selected clusters of galaxies…

She et al. (Paper I) assembled a catalog of nearby galaxies observed with the Chandra X-ray observatory, by cross-matching galaxies in the NASA Extragalactic Database (NED) within 50 Mpc and the Chandra archive. That sample has enabled…

We present a Chandra/ACIS-I study of X-ray sources in BOSS 1441, a protocluster at $z=2.32\pm0.02$ that exhibits a prominent overdensity of Ly$\alpha$ emitters (LAEs). Using a 45 ks observation, we identify seven X-ray sources spatially…

We discuss ROSAT HRI X-ray observations of 33 very nearby galaxies, sensitive to X-ray sources down to a luminosity of approximately 10^38 erg/s. The galaxies are selected from a complete, volume limited sample of 46 galaxies with d<7 Mpc…