1,350 datasets found

The flat-spectrum radio quasar (FSRQ) 4C +01.28 is a bright and highly variable radio and gamma-ray emitter. We aim to pinpoint the location of the gamma-ray emitting region...

We present a catalog of unobscured quasi-stellar object (QSO) candidates in the Southern Hemisphere from the early interim data of the KMTNet Synoptic Survey of Southern Sky...

We analyze the optical variability of the flat-spectrum radio quasar (FSRQ) Ton 599 using BVRI photometry from the WEBT Collaboration (2011-2023), complemented by Steward...

We present monitoring observations of quasar microlensing in the quadruple quasar HE0435-1223. The microlensing-induced light curves of the quasar images are chromatic, i.e....

The formation of the first supermassive black holes is expected to have occurred in some most pronounced matter and galaxy overdensities in the early universe. We have conducted...

We present results of a systematic search for gravitationally lensed quasars in Pan-STARRS1. Our final sample of candidates comprises of 91 systems, not including 25...

We present the first results from a study of OVI absorption around galaxies at z<1.44 using data from a near-infrared grism spectroscopic Hubble Space Telescope Large...

We present 1-7GHz high-resolution radio imaging (VLA and e-MERLIN) and spatially resolved ionized gas kinematics for 10 z<0.2 type 2 'obscured' quasars...

We use the MusE GAs FLOw and Wind (MEGAFLOW) survey to study the kinematics of extended disc-like structures of cold gas around z=~1 star-forming galaxies. The combination of...

We study the morphological and structural properties of the host galaxies associated with 57 optically selected luminous type 2 active galactic nuclei (AGNs) at z~0.3-0.4: 16...

Around 10 per cent of bright low-frequency radio sources observed with the Murchison Wide-field Array (MWA) show strong interplanetary scintillation (IPS) on time-scales of a...

We present the first data release (DR1) of the UVES Spectral Quasar Absorption Database (SQUAD), comprising 467 fully reduced, continuum-fitted high-resolution quasar spectra...

Dust plays a pivotal role in the chemical enrichment of the interstellar medium. In the era of mid-/high-resolution spectra and multiband spectral energy distributions, testing...

Narrow-line regions excited by active galactic nuclei (AGNs) are important for studying AGN photoionization and feedback. Their strong [OIII] lines can be detected with...

investigated narrow-line Seyfert 1 galaxies (NLS1s) at optical, mid-infrared (MIR), and X-ray wavelengths, comparing them to the broad-line active galactic nuclei (BLAGNs). We...

Most active galactic nuclei (AGNs) are radio quiet, and the origin of their radio emission is not well understood. One hypothesis is that this radio emission is a byproduct of...

We present the results of our automatic search for proximate damped Ly{alpha} absorption (PDLA) systems in the quasar spectra from the Sloan Digital Sky Survey Data Release 12....

The gamma-ray emission in broad-line blazars is generally explained as inverse Compton (IC) radiation of relativistic electrons in the jet scattering optical-UV photons from the...

We present a sample of 34 weak metal line absorbers at z<0.3 selected by the simultaneous >3{sigma} detections of the SiII{lambda}1260 and CII{lambda}1334 absorption...

We present the first short time-scale (~ hours to days) optical variability study of a large sample of active galactic nuclei (AGNs) observed with the Kepler/K2 mission. The...