X-ray polarization from accretion disk winds

Anagha P. Nitindala, Alexandra Veledina, Juri Poutanen

Published 2024-11-27Version 1

X-ray polarimetry is a fine tool to probe the accretion geometry and physical processes operating in the proximity of compact objects, black holes and neutron stars. Recent discoveries made by the Imaging X-ray Polarimetry Explorer put our understanding of the accretion picture in question. The observed high levels of X-ray polarization in X-ray binaries and active galactic nuclei are challenging to achieve within the conventional scenarios. In this work we investigate a possibility that a fraction (or even all) of the observed polarized signal arises from scattering in the equatorial accretion disk winds, the slow and extended outflows, which are often detected in these systems via spectroscopic means. We find that the wind scattering can reproduce the levels of polarization observed in these sources.