High Energy Astrophysics and Cosmology in the era of all-sky surveys

Session

AGN

19 Jun 2026, 14:30

39. Reflection-dominated CT AGN candidates — first SRG/eROSITA results from the Eastern Galactic hemisphere

Mikhail Belvedersky (IKI RAS)

19/06/2026, 14:30

We describe a population of AGNs with extremely hard spectra found among the sources registered by SRG/eROSITA on the Eastern Galactic hemisphere. Such spectra cannot be explained by inverse Compton scattering typical of “normal” AGNs, but can be produced by the X-ray emission reflected from a dusty torus, indicating significant obscuration (up to the Compton-thick regime). We developed a...

10. From spectral energy distribution to line suppression: probing the physics of the X-ray-weak WLQ SDSS J101353.45+492758.1

Laetitia Gibaud (Faculty of Physics, University of Bialystok)

19/06/2026, 14:50

Weak-emission-line quasars (WLQs) represent an extreme subclass of active galactic nuclei (AGNs), displaying unusually faint or absent emission lines despite luminous quasar-like continua. The source SDSS J101353.45+492758.1 is a particularly striking example, characterized by a nearly lineless UV–optical spectrum and a pronounced X-ray weakness.

We first analyze its broadband spectral...

42. A novel approach to the relation between X-ray and ultraviolet luminosities of quasars using SRG/eROSITA and SDSS data

Sergey Prokhorenko (Space Research Institute of the Russian Academy of Sciences (IKI))

19/06/2026, 15:10

The statistical analysis of the relationship between ultraviolet (UV) and X-ray emission from active galactic nuclei (AGN) allows for a better understanding of the processes occurring during accretion of matter onto a supermassive black hole in the center of AGN, and also tests the possibility of using quasars as "standard candles" for measuring distances on cosmological scales in the...

56. Study of X-ray and optical spectral properties of AGN from the SRG/ART-XC All-Sky Survey using Swift/XRT and SDSS archival data

Aleksei Sokolov (IKI RAS)

19/06/2026, 15:30

We present the results of our analysis of the X-ray spectra of a large subsample of active galactic nuclei (AGN) from the catalog of sources detected by the Mikhail Pavlinsky ART-XC telescope aboard the SRG orbital observatory during its all-sky survey (ARTSS1-5). The analysis is based on archival observations with the Swift/XRT telescope in the 1–10 keV energy range. For all sources, we...