10–14 Nov 2025
Europe/Prague timezone

Effects of Strong Gravity on the Warm Corona in AGN

12 Nov 2025, 15:50
20m

Speaker

Parikshit Partha Biswas (Nicolaus Copernicus Astronomical Center, Warsaw)

Description

We explore the inner regions of an accretion flow in Active Galactic Nuclei (AGN), where we consider a warm corona to be on top of the accretion disk, acting like a disk atmosphere. The warm corona is assumed to be dissipative, and it is illuminated by the external X-ray lamp at the surface and by the cold disk flux at the bottom. We study this scenario by radially stratifying the accretion disk atmosphere and computing the vertical structure at each radial point using the photoionization code TITAN. Then we feed the whole radial structure into the ray-tracing code GYOTO, where we include the relativistic effects on the emission from these inner regions of the accretion disk atmosphere. This study helps us to compute the spectral emission and features that can be studied from the inner region of the accretion disk. The existence of the warm corona shows the deviation of the emissivity radial profile from that of a bare standard disk. This also shows that the accretion disk atmosphere can be hot, emitting highly ionized Fe Kɑ line that are subjected to relativistic corrections. The main aim of this study is to investigate the effect of these lines and their structural changes with the change in spin of the supermassive black hole and the viewing angle of an observer in the regime of strong gravity.

Primary author

Parikshit Partha Biswas (Nicolaus Copernicus Astronomical Center, Warsaw)

Co-authors

Prof. Agata Różańska (Nicolaus Copernicus Astronomical Center, Warsaw, Poland) Debora Lančová (Institute of Physics, Silesian University in Opava) Prof. Frederic Vincent (CNRS, Paris) Prof. Piotr Zycki (Nicolaus Copernicus Astronomical Center, Warsaw, Poland)

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