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Quasars and Active Galactic Nuclei (8th Ed.)
This catalogue (with updates to the pervious version) contains 11358 (+2759) quasars (defined as brighter than absolute B magnitude -23), 3334 (+501) AGNs (defined as fainter... -
Microquasar V4641 Sgr image
Microquasars have emerged as promising candidates to explain the cosmic-ray flux at PeV energies. LHAASO observations reveal V4641 Sgr as the most extreme example so far, with a... -
miniJPAS survey quasar selection. V.
Quasar catalogues from narrow-band photometric data are used in a variety of applications, including targeting for spectroscopic follow-up, measurements of supermassive black... -
SDSS DR10 catalogue of candidate quasars
We discuss whether modern machine learning methods can be used to characterize the physical nature of the large number of objects sampled by the modern multi-band digital... -
Observations & positions of 377 AGNs using VLBI
Active galactic nuclei (AGNs) observed with the very long baseline interferometry (VLBI) technique are used as fiducial references on the sky to precisely measure the shape and... -
Spectra of lensed QSOs (SSAP)
An archive of optical and near-infrared spectra of strongly lensed quasars and the lensing galaxies. The spectra are resolved to about a few Ångstroms and are flux-calibrated.... -
Lens Image Archive
A collection of images of lensed quasars from various sources. Included are images from Maidanak Observatory (ivo://org.gavo.dc/maidanak/res/rawframes/siap), Apache Point... -
Maidanak Observatory Lens Images
Reduced frames of lensed quasar observations from Maidanak Observatory. See the referenceURL for details on the reduction procedure and calibration data. -
Apache Point observations of lensed quasars
Observations of the lensed quasar Q2237+0305 performed between 1995 and 1998. -
Liverpool Quasar Lens Monitoring
This collection includes optical monitorings of gravitationally lensed quasars. The frames can be used to make light curves of quasar images and field objects. From quasar light... -
QSOs CaII absorbers
We present a systematic study of weak intervening CaII absorbers at low redshift (z<0.5), based on the analysis of archival high-resolution (R>=45000) optical spectra of... -
IGM metal enrichment with UVES deep spectrum
The distribution and the abundance of metals in the intergalactic medium (IGM) have strong implications for galaxy formation and evolution models. The ionic transitions of heavy... -
eRASS1 counterparts and classification
Accurately accounting for the AGN phase in galaxy evolution requires a large, clean AGN sample. This is now possible with SRG/eROSITA, which completed its first all-sky X-ray... -
Re-classification of high-redshift QSOs
The discovery of outsiders in the form of unusual, rare, or even unknown object types is important as they can provide useful information about otherwise hidden physical... -
Properties of type 1 AGNs
We examine the connection between galaxy mergers and the triggering of active galactic nuclei (AGNs) using a sample of 614 type 1 AGNs at z<0.07, along with a control sample... -
Gamma-ray emitting region location in 4C +01.28
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... -
Unobscured QSO cand. in the southern sky with KS4
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... -
Multiband optical variability of blazar Ton 599
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... -
HE0435-1223 V and R light curves
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....
