Related papers: Optical Identification of the ASCA Large Sky Surve…

We report optical spectroscopic identifications of 10 hard (2-10 keV) X-ray selected sources discovered by Chandra. The X-ray flux of the sources ranges between 1.5 and 25 x 10-14 cgs, the lower value being 3 times fainter than in previous…

(abridged) We present a catalog of 2357 point sources detected during 590 ks of Chandra observations of the 17-by-17 arcminute field around Sgr A*. This field encompasses a physical area of 40 by 40 pc at a distance of 8 kpc. The…

We present X-ray spectra of 185 bright sources detected in the XMM-Newton deep survey of the Chandra Deep Field South, combining the three EPIC cameras. The 2-10 keV flux limit of the sample is 2e-15 erg/s/cm2. The sources are distributed…

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 X-ray and optical analysis of 188 AGN identified from 497 hard X-ray (f (2.0-8.0 keV) > 2.7x10^-15 erg cm^-2 s^-1) sources in 20 Chandra fields (1.5 deg^2) forming part of the Chandra Multi-wavelength Project. These medium depth…

We present the results of our identification of 11 X-ray sources detected on the half of the sky $0^\circ<l<180^\circ$ in the 4-12 keV energy band on the combined map of the first five all-sky surveys with the Mikhail Pavlinsky ART-XC…

We provide X-ray constraints and perform the first X-ray spectral analyses for bright (f_850>=5mJy; S/N>=4) SCUBA sources in an 8.4'x8.4' area of the 2 Ms Chandra Deep Field-North survey containing the Hubble Deep Field-North. X-ray…

The 13hr XMM-Newton/Chandra deep survey is the first of two extremely deep XMM-Newton fields observed by the XMM-OM consortium. A 120 ks Chandra mosaic, covering 0.2 square degrees, provides sensitive, confusion-free point source detection…

We discuss the optical and X-ray spectral properties of the sources detected in a single 200ks Chandra pointing in the Groth-Westphal Strip region. Optical identifications and spectroscopic redshifts are primarily from the DEEP2 survey.…

We describe in this paper the ROSAT Ultra Deep Survey (UDS), an extension of the ROSAT Deep Survey (RDS) in the Lockman Hole. The UDS reaches a flux level of 1.2 x 10E-15 erg/cm2/s in 0.5-2.0 keV energy band, a level ~4.6 times fainter than…

The spectroscopic analysis of 117 serendipitous sources in the HELLAS2XMM 1df (1 degree field) survey is described. Of these, 106 sources, of which 86% have a spectroscopic redshift, are used to evaluate the fraction of X-ray absorbed (log…

Using the Chandra ACIS-I instruments, we have carried out a deep X-ray observation on the Galactic plane region at (l,b) ~ (28.5, 0.0), where no discrete X-ray sources have been known previously. We have detected, as well as strong diffuse…

We develop a new diagnostic method to classify galaxies into AGN hosts, star-forming galaxies, and absorption-dominated galaxies by combining the [O III]/Hbeta ratio with rest-frame U-B color. This can be used to robustly select AGNs in…

X-rays offer a reliable method to identify Active Galactic Nuclei (AGN). However, in the high-redshift Universe X-ray AGN are poorly sampled due to their relatively low space density and the small areas covered by X-ray surveys. In addition…

We present optical spectroscopic identifications of hard X-ray (5-10 keV) selected sources belonging to the HELLAS sample obtained with BeppoSAX down to a 5-10 keV flux limit of f_{5-10 keV}~3x10^-14 erg cm^-2 s^-1. The sample consists of…

We present results from a Chandra X-ray Observatory study of the field X-ray source populations in 4 different observations: two high-redshift (z~0.5) clusters of galaxies 3C295 and RXJ003033.2+261819; and two non-cluster fields with…

We present the statistical evaluation of a count rate and area limited complete sample of the ROSAT All-Sky Survey (RASS) comprising 674 sources. The RASS sources are located in six study areas outside the galactic plane (|b^II| >= 20 deg)…

The X-ray emission from the central region of the Galactic plane, |l|<45 deg and |b|<0.4 deg, was studied in the 0.7-10 keV energy band with a spatial resolution of ~3' with the ASCA observatory. We developed a new analysis method for the…

The edge-on spiral galaxy NGC 4565 was observed for $\sim$ 35 ks with ASCA in the 0.5-10 keV energy band. The X-ray emission was dominated by two bright sources, which can be identified with two point-like X-ray sources seen in the ROSAT…

We report the final optical identifications of the medium-depth (~60 ksec), contiguous (2 deg^2) XMM-Newton survey of the COSMOS field. XMM-Newton has detected ~800 X-ray sources down to limiting fluxes of ~5x10^{-16}, ~3x10^{-15}, and…