Related papers: X-Ray Surveys
The XMM-Newton Slew Survey (XSS) covers a significant fraction of the sky in a broad X-ray bandpass. Although shallow by contemporary standards, in the `classical' 2-10 keV band of X-ray astronomy, the XSS provides significantly better…
An analysis of the spatial fluctuations in 15 deep ASCA SIS0 images has been conducted in order to probe the 2-10 keV X-ray source counts down to a flux limit 2E-14 erg/cm2/s. Special care has been taken in modelling the fluctuations in…
We present observations in the 0.1-100 keV spectral band of 8 Seyfert 2 galaxies, obtained by means of BeppoSAX. These sources were selected according to their [OIII] optical emission line flux, to avoid biases against obscuration on the pc…
We present new BeppoSAX LECS, MECS, and PDS observations of five lobe-dominated, broad-line active galactic nuclei selected from the 2 Jy sample of southern radio sources. These include three radio quasars and two broad-line radio galaxies.…
The origin of the X-ray background spectral intensity has been a long standing problem in high energy astrophysics research. Deep X-ray surveys carried out with ROSAT and ASCA combined with the broad band spectral results of Ginga and…
AXIS (An XMM-Newton International Survey) is a survey of 36 high Galactic latitude XMM-Newton observations covering 4.8 deg2 and containing 1433 serendipitous X-ray sources detected with 5-sigma significance. We have studied the X-ray…
Deep surveys of the cosmic X-ray background are reviewed in the context of observational progress enabled by the Chandra X-ray Observatory and the X-ray Multi-Mirror Mission-Newton. The sources found by deep surveys are described along with…
We have searched the entire ROSAT archive for useful observations to study X-ray emission from Galactic planetary nebulae (PNs). The search yields a sample of 63 PNs, which we call the ROSAT PN sample. About 20-25% of this sample show X-ray…
Optical identification of hard X-ray selected BeppoSAX and Chandra sources indicates that a large fraction of the sources are ``intermediate'' AGN, i.e. type 1.8-1.9 AGN, broad-line quasars and even X-ray loud but optically dull (apparently…
We have discovered four AGN in the ROSAT all-sky-survey data with very steep X-ray spectra. We apply several models to these X-ray spectra with emphasis on warm absorber models which give an adequate description of the data. We report on…
In order to derive statistical properties of a complete X-ray selected sample of AGN we used the classification spectra of the RASS Selected Areas-North survey to study the luminosities, redshifts, X-ray/visual flux ratios, line widths, and…
While the cosmic soft X-ray background is very likely to originate from individual Seyfert galaxies, the origin of the cosmic hard X-ray and MeV gamma-ray background is not fully understood. It is expected that Seyferts including Compton…
The high angular resolution and sensitivity of the Chandra X-ray Observatory has yielded large numbers of faint X-ray sources with measured redshifts in the soft (0.5-2 keV) and hard (2-8 keV) energy bands. Many of these sources show few…
The properties of Compton-thick AGN are reviewed, with particular emphasis on BeppoSAX hard X-ray observations. I also discuss evidence for the presence of Compton-thick, circumnuclear matter in unobscured AGN, and I briefly introduce the…
We present the results of a deep X-ray survey conducted with XMM-Newton, centred on the UK ROSAT 13H deep field area. This region covers 0.18 deg^2 and is the first of two areas covered with XMM-Newton as part of an extensive…
We present new results on the cosmological evolution of unabsorbed (type-1) active galactic nuclei (AGN) selected in the soft (0.5-2 keV) X-ray band. From a variety of ROSAT, XMM-Newton and Chandra surveys we selected a total of ~1000 AGN…
We present the Extragalactic Serendipitous Swift Survey (ExSeSS), providing a new well-defined sample constructed from the observations performed using the Swift X-ray Telescope. The ExSeSS sample consists of 79,342 sources detected in the…
We present first results from the ASCA Medium Sensitivity Survey (AMSS; or the GIS catalog project). From the serendipitous fields amounting to 106 degE-2, we determined the Log N - Log S relations in the 0.7-7 keV and 2-10 keV bands with…
We observed the nearby galaxy M~51 (NGC 5194) with BeppoSAX. The X-ray properties of the nucleus below 10 keV are almost the same as the ASCA results regarding the hard component and the neutral Fe K$\alpha$ line, but the intensity is about…
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…