X-ray Polarization from Accreting Black Holes: Coronal Emission - Astrophysics > High Energy Astrophysical PhenomenaReportar como inadecuado




X-ray Polarization from Accreting Black Holes: Coronal Emission - Astrophysics > High Energy Astrophysical Phenomena - Descarga este documento en PDF. Documentación en PDF para descargar gratis. Disponible también para leer online.

Abstract: We present new calculations of X-ray polarization from accreting black holesBHs, using a Monte-Carlo ray-tracing code in full general relativity. In ourmodel, an optically thick disk in the BH equatorial plane produces thermal seedphotons with polarization oriented parallel to the disk surface. These seedphotons are then inverse-Compton scattered through a hot but thermal corona,producing a hard X-ray power-law spectrum. We consider three different modelsfor the corona geometry: a wedge ``sandwich- with aspect ratio H-R andvertically-integrated optical depth tau 0 constant throughout the disk; aninhomogeneous ``clumpy- corona with a finite number of hot clouds distributedrandomly above the disk within a wedge geometry; and a spherical corona ofuniform density, centered on the BH and surrounded by a truncated thermal diskwith inner radius R edge. In all cases we find a characteristic transition fromhorizontal polarization at low energies to vertical polarization above thethermal peak; the vertical direction is defined as the projection of the BHspin axis on the plane of the sky. We show how the details of thespectropolarization signal can be used to distinguish between these models andinfer various properties of the corona and BH. Although the bulk of this paperfocuses on stellar-mass BHs, we also consider the effects of coronal scatteringon the X-ray polarization signal from supermassive BHs in active galacticnuclei.



Autor: Jeremy D. Schnittman, Julian H. Krolik Johns Hopkins

Fuente: https://arxiv.org/







Documentos relacionados