English (United Kingdom)

https://curated-unify.zendy.io/wp-json/zendy-region/v1/featured_content/oa?rat=en

https://curated-unify.zendy.io/wp-json/zendy-region/v1/highlighted_journal/

Global: Zendy Plus annual

Presents the access of premium content as premium feature

Premium Content

Presents the keyphrase highlighting as premium feature

Keyphrase Highlighting

Presents the summarisation as premium feature

Summarisation

Insights

Presents the pdf analysis as premium feature

PDF Analysis

Presents the zaia usage as premium feature

ZAIA

Global: Zendy Tools annual

Global: Zendy Free Plan

Global: Zendy Tools monthly

Global: Zendy Plus monthly

Accretion disks around stellar-mass black holes (BHs) emit radiation peakingin the soft X-rays when the source is in the thermal state. The emergingphotons are polarized and, for symmetry reasons, the polarization integratedover the source is expected to be either parallel or perpendicular to the(projected) disk symmetry axis, because of electron scattering in the disk.However, due to General Relativity effects photon polarization vectors willrotate with respect to their original orientation, by an amount depending onboth the BH spin and the observer's inclination. Hence, X-ray polarizationmeasurements may provide important information about strong gravity effectsaround these sources. Along with the spectral and polarization properties ofradiation which reaches directly the observer once emitted from the disk, inthis paper we also include the contribution of returning radiation, i.e.photons that are bent by the strong BH gravity to return again on the disk,where they scatter until eventually escaping to infinity. A comparison betweenour results and those obtained in previous works by different authors show anoverall good agreement, despite the use of different code architectures. Wefinally consider the effects of absorption in the disk material by includingmore realistic albedo profiles for the disk surface. Our findings in thisrespect show that considering also the ionization state of the disk may deeplymodify the behavior of polarization observables.

Towards a complete description of spectra and polarization of black hole accretion disks: albedo profiles and returning radiation