Soft X-Ray and Ultraviolet Emission Relations in Optically Selected AGN Samples

  title={Soft X-Ray and Ultraviolet Emission Relations in Optically Selected AGN Samples},
  author={Iskra V. Strateva and Niel Brandt and Donald P. Schneider and Daniel E. vanden Berk and Cristian Vignali Penn State and University of Bologna},
  journal={The Astronomical Journal},
Using a sample of 228 optically selected active galactic nuclei (AGNs) in the 0.01–6.3 redshift range with a high fraction of X-ray detections (81%–86%), we study the relation between rest-frame UV and soft X-ray emission and its evolution with cosmic time. The majority of the AGNs in our sample (155 objects) have been selected from the Sloan Digital Sky Survey (SDSS) in an unbiased way, rendering the sample results representative of all SDSS AGNs. The addition of two heterogeneous samples of… 
The X-Ray-to-Optical Properties of Optically Selected Active Galaxies over Wide Luminosity and Redshift Ranges
We present partial-correlation analyses that examine the strengths of the relationships between l2500 A, l2 keV, αOX, and redshift for optically selected active galactic nuclei (AGNs). We extend the
The X-ray to optical-UV luminosity ratio of X-ray selected type 1 AGN in XMM-COSMOS
We present a study of the X-ray to optical properties of a sample of 545 X-ray selected type 1 AGN, from the XMM-COSMOS survey, over a wide range of redshifts (0.04 \textless z \textless 4.25) and
An X-ray survey in SA 57 with XMM-Newton
Context. The maximum number density of Active Galactic Nuclei (AGNs), as deduced from X-ray studies, occurs at z < 1, with lower luminosity objects peaking at smaller redshifts. Optical studies lead
Optical-to-X-ray emission in low-absorption AGN: results from the Swift–BAT 9-month catalogue
We present simultaneous optical-to-X-ray spectral energy distributions (SEDs) from Swift's X-ray and UV-optical telescopes (XRTs and UVOTs) for a well-selected sample of 26 low-redshift (z < 0.1)
The correlation of narrow line emission and X-ray luminosity in active galactic nuclei
Aims. We combine emission line and X-ray luminosities for 45 sources from the Chandra Deep Field South (CDF-S), and seven HELLAS sources, to obtain a new sample of 52 X-ray selected type-II active
Measuring the Sources of the Intergalactic Ionizing Flux
We use a wide-field (0.9 deg2) X-ray sample with optical and Galaxy Evolution Explorer (GALEX) ultraviolet observations to measure the contribution of active galactic nuclei (AGNs) to the ionizing
Variability and spectral energy distributions of low-luminosity active galactic nuclei: a simultaneous X-ray/UV look with Swift
We have observed four low-luminosity active galactic nuclei (AGNs) classified as type 1 Low-Ionization Nuclear Emission-Line Regions (LINERs) with the X-Ray Telescope (XRT) and the
The soft X-ray properties of quasars in the Sloan Digital Sky Survey
We use the ROSAT All-Sky Survey (RASS) to study the soft X-ray properties of a homogeneous sample of 46 420 quasars selected from the third data release of the Sloan Digital Sky Survey (SDSS).
The tight relation between X-ray and ultraviolet luminosity of quasars
The observed relation between the soft X-ray and the optical-ultraviolet emission in active galactic nuclei (AGN) is non-linear and it is usually parametrized as a dependence between the logarithm of
Evolution of the X-ray Emission of Radio-quiet Quasars
We report new Chandra observations of seven optically faint, z ~ 4 radio-quiet quasars (RQQs). We have combined these new observations with previous Chandra observations of RQQs to create a sample of


The X-ray properties of high-redshift quasi-stellar objects
Sensitive X-ray information is presented for about 90 previously uncataloged high-redshift, optically selected QSOs. Two high-redshift subsets of this larger data base are emphasized: (1) a
X-ray emission from radio-quiet quasars in the SDSS Early Data Release. The alpha_ox dependence upon UV luminosity
We investigate the X-ray properties of the color-selected radio-quiet quasars (RQQs) in the Sloan Digital Sky Survey (SDSS) Early Data Release using ROSAT, Chandra, and XMM-Newton data. In the
When supermassive black holes were growing: clues form deep X-ray surveys
Merging the Chandra and XMM-Newton deep surveys with the previously identified ROSAT sample, almost 1000 AGN-1 covering five orders of magnitude in 0.5-2 keV flux limit and six orders of magnitude in
X-ray studies of quasars with the Einstein observatory
Using the Einstein Observatory, we have carried out X-ray observations of 107 quasars and have detected 79. From the analysis of this sample of objects we find a correlation between optical emission
X-Ray properties of optically selected QSOs
The dependence of the X-ray-to-optical luminosity ratio on optical luminosity and redshift for optically selected QSOs is studied, largely on the basis of two, complete, magnitude-limited samples
X-Ray Spectroscopy of Quasi-Stellar Objects with Broad Ultraviolet Absorption Lines
For the population of quasi-stellar objects (QSOs) with broad ultraviolet absorption lines, we are just beginning to accumulate X-ray observations with enough counts for spectral analysis at CCD
X-Ray Insights into Interpreting C IV Blueshifts and Optical/Ultraviolet Continua
We present 0.5?8.0 keV Chandra observations of six bright quasars that represent extrema in quasar emission-line properties?three quasars each with small and large blueshifts of the C IV emission
Chandra survey of radio-quiet, high-redshift quasars
We observed 17 optically selected, radio-quiet, high-redshift quasars with the Chandra ACIS and detected 16 of them. The quasars have redshifts between 3.70 and 6.28 and include the highest-redshift
X-ray properties of quasars and results from a deep X-ray survey of optically selected objects
A sample of 178 optically selected quasars and Seyfert galaxies is studied. Seventy seven of the objects have measured X-ray fluxes while the remainder have upper limits. The analysis strengthens and
We report on Chandra and XMM-Newton observations of a sample of 13 quasars at z ? 4.7?5.4 mostly taken from the Sloan Digital Sky Survey (SDSS). The present sample complements previous X-ray studies