1,216 datasets found

We investigate the responsiveness of the 2798{AA} MgII broad emission line in active galactic nuclei (AGNs) on time-scales of several years. Our study is based on a sample of...

Radio-loud quasars (RLQs) are more X-ray luminous than predicted by the X-ray-optical/UV relation (i.e. L_x_{prop.to}L_uv_^{gamma}^) for radio-quiet quasars (RQQs). The excess...

We study the ultraviolet (UV) emission-line ratios of a sample of 145 type II quasars (QSO2s) from Sloan Digital Sky Survey III Baryon Oscillation Spectroscopic Survey, and...

Following its launch in 2008 June, the Fermi Gamma-ray Space Telescope (Fermi) began a sky survey in August. The Large Area Telescope (LAT) on Fermi in three months produced a...

We have recently found fundamental differences in the radio properties of red quasars when compared to typical blue quasars. In this paper we use data from the X-shooter...

Striking similarities have been seen between accretion signatures of Galactic X-ray binary (XRB) systems and active galactic nuclei (AGNs). XRB spectral states show a V-shaped...

Recent NuSTAR observations revealed a somewhat unexpected increase in the X-ray flux of the nucleus of NGC 1068. We expect the infrared emission of the dusty torus to react on...

The Wide-field Infrared Survey Explorer (WISE) mission has unveiled a rare population of high-redshift (z=1-4.6), dusty, hyper-luminous galaxies, with infrared luminosities...

This is a compendium of 607,208 type-I QSOs and AGN, largely complete from the literature to 5-August-2017, including the release of SDSS-DR14. Also included are ~1.35M...

We present the Palermo Swift-BAT hard X-ray catalogue obtained from the analysis of the the data relative to the first 39 months of the Swift mission. We have developed a...

We study the long-term variability in the optical monitoring database of Ark 120, a nearby radio-quiet active galactic nucleus (AGN) at a distance of 143Mpc (z=0.03271). We...

We report on 167 infrared (IR) galaxies selected by AKARI and IRAS and detected in the Atacama Cosmology Telescope (ACT) Data Release 5 (DR5) sky maps at the 98, 150, and 220GHz...

We present Spitzer observations for a sample of close major-merger galaxy pairs (KPAIR sample) selected from cross-matches between the 2MASS Extended Source Catalog and Sloan...

Radio outflows of active galactic nuclei (AGNs) are invoked in cosmological models as a key feedback mechanism in the latest phases of massive galaxy formation. Recently, it has...

Active galactic nuclei (AGNs), particularly the most luminous AGNs, are commonly assumed to be triggered through major mergers; however, observational evidence for this scenario...

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In the framework of the Standard Model Extension (SME), we present improved constraints on anisotropic Lorentz invariance and Charge-Parity-Time (CPT) violation by searching for...

This catalogue is an update of the previous versions. The recent release of the final release of the 2dF quasar catalogue and of the first part of the SLOAN catalogue, almost...

We present the X-ray catalog and basic results from our Chandra Large Area Synoptic X-ray Survey (CLASXS) of the Lockman Hole-Northwest (LHNW) field. Our nine ACIS-I fields...

Variability is one of the most observable characteristics of active galactic nuclei, and it is important when considering the emission mechanism. In this paper, we report...