Polarization of emission from black hole accretion disks: including returning radiation

0567704 - ASÚ 2023 RIV SG eng C - Conference Paper (international conference)
Taverna, R. - Bursa, Michal - Dovčiak, Michal - Karas, Vladimír - Marin, F. - Matt, G. - Mikušincová, R. - Zhang, W.
Polarization of emission from black hole accretion disks: including returning radiation.
The Fifteenth Marcel Grossmann Meeting: On Recent Developments in Theoretical and Experimental General Relativity, Astrophysics, and Relativistic Field Theories. Singapore: World Scientific, 2022 - (Battistelli, E.; Jantzen, R.; Ruffini, R.), s. 250-257. ISBN 978-981-125-825-1.
[Marcel Grossmann Meeting on General Relativity /15./. Rome (IT), 01.07.2018-07.07.2018]
Institutional support: RVO:67985815
Keywords : polarization * relativity * polarimeters
OECD category: Astronomy (including astrophysics,space science)

Accretion disks around stellar-mass black holes (BHs) are observed to emit radiation peaking in the soft X-rays (at about 1 keV) when the source is in the thermal state. This emission is expected to be polarized, because of electron scattering in the disk. However, photons will experience a rotation of the polarization plane due to General Relativity effects. X-ray polarization measurements can then be crucial in assessing strong gravity effects around accreting stellar-mass BHs, providing independent constraints on their spin. In this work, we present the simulated polarization spectra (obtained according to the model by Dovčiak et al.) for the X-ray, thermal radiation emitted by the accretion disk, as expected to be measured by IXPE, an X-ray polarimeter which will be launched in 2021. We also illustrate the code, currently under development, incorporate the contribution of returning radiation and account for absorption effects by the disk material.
Permanent Link: https://hdl.handle.net/11104/0338936