1,385 datasets found

High spectral resolution (FWHM = 0.6 or 0.35 {AA}) were obtained for six high redshift QSOs, z_em_ > 2.2, containing lines from 31 metal-rich absorption line systems amongst...

We present the second data release (DR2) of the XXL Survey, contextually with the appearance of a second A&A special issue dedicated to XXL. This intermediate release...

The quest for the cosmological parameters that describe our universe continues to motivate the scientific community to undertake very large survey initiatives across the...

The Einstein Deep Survey program (EDS) consists of very deep X-ray exposures in selected regions of the sky at high galactic latitude. The main purposes of the survey are to...

A search for faint blue stars conducted at the Observatories of Tonantzintla and Minnesota has yielded 8746 objects which are somewhat blue. The data file is organized into...

This atlas contains the ultraviolet spectra of 70 quasars, blazars, and Seyfert 1 galaxies that were produced by combining over 100 low resolution spectra from the International...

We present the second public data release of the VISTA EXtension to Auxiliary Surveys (VEXAS DR2), where we classify objects into stars, galaxies and quasars based on an...

This catalogue is an update of the previous versions. It contains 13214 (+1856) quasars (defined as brighter than absolute B magnitude -23), 4428 (+1094) AGNs (defined as...

This catalogue is an update of the the previous versions. It contains 8609 (+172) quasars (defined as brighter than absolute B magnitude -23), 2833 (+978) AGNs (defined as...

(Paper I) We provide details of a multicolor ( u, b_j_, v, or, r, i), wide-field, faint magnitude survey for high-redshift (z >= 2.2 ) quasars. The survey extends over the...

(no description available) Cone search capability for table VII/181/table2 (Catalog for PG Quasars) Cone search capability for table VII/181/table3 (Catalog for Seyfert 1 and...

The objects of this catalogue were detected by using the 61-cm aperture Curtis Schmidt telescope in combination with a thin objective prism (1.8{deg}) at the Cerro Tololo...

We present the results of optical spectroscopy for 58 quasar candidates at photometric redshifts z>~3, 57 of which enter into the Khorunzhev et al. (2016, Cat. J/PAZh/42/313)...

This data set is based on data in three publications. The positions and magnitudes of quasar candidates discovered on Canada-France Hawaii-Telescope (CFHT) blue green plates are...

In the blazar catalog BZCAT the objects are divided into 4 types: BZB, BZQ, BZG, and BZU. In this paper BZG objects are studied in order to determine their physical nature. Of...

The second part of the First Byurakan Survey is aimed at detecting all bright (B<16.5) UV-excess starlike objects in a large area of the sky. By comparison with other major...

We present a study of the multiwavelength (MW) variability of the blazar AO 0235+164 based on the radio-to-gamma-ray data covering a long time period from 1997 to 2023. The...

Understanding the links between different phases of outflows from active galactic nuclei is a key goal in extragalactic astrophysics. Here, we compare [OIII] {lambda}{lambda}...

The eROSITA X-ray telescope on board the Spectrum-Roentgen-Gamma (SRG) spacecraft observed the field of the UKIDSS Ultra-Deep Survey (UDS) in August-September 2019, during its...

Here we present the first optical photometric monitoring results of a sample of twelve newly discovered blazars from the ICRF - Gaia CRF astrometric link. The observations were...