Space and Cosmic Ray Physics Seminar for 2018-02-12

Series: Space and Cosmic Ray Physics Seminar
Date: Monday 12-Feb-2018
Time: 4:30 pm
Location: ATL 2400
Speaker: Demos Kazanas (NASA Goddard)
Title: MHD Accretion Disk Winds as X-Ray Absorbers Across the Black Hole Mass Scale

Black hole accretion disks appear to produce invariably plasma outflows that result in blue-shifted absorption features in their X-ray and UV spectra. The X-ray absorption-line properties of these outflows are quite diverse, ranging in velocity from non-relativistic (~300 km/sec) to sub-relativistic (~0.1c where c is the speed of light) and a similarly broad range in the ionization states of the wind plasma. It will be shown that semi-analytic, self-similar magnetohydrodynamic (MHD) wind models can successfully account for the X-ray absorber properties of supermassive black holes and also that the same models fit well the high-resolution X-ray spectrum of the accreting stellar-mass black hole, GRO J1655-40. This provides an explicit theoretical argument of their MHD origin (aligned with earlier observational claims) and supports the notion of a universal magnetic structure of the observed winds across all known black hole sizes. Most importantly, these results! indicate that the mass flux of these winds increases with radius, a fact that bears on the global structure of Active Galactic Nuclei (AGN) and Galactic X-Ray Sources (XRB).

Notes: Coffee, Tea & Snacks 4:15-4:30 PM

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