Modeling Emission from the Supermassive Black Hole in the Galactic Center with GRMHD Simulations - Astrophysics > High Energy Astrophysical PhenomenaReportar como inadecuado




Modeling Emission from the Supermassive Black Hole in the Galactic Center with GRMHD Simulations - Astrophysics > High Energy Astrophysical Phenomena - Descarga este documento en PDF. Documentación en PDF para descargar gratis. Disponible también para leer online.

Abstract: Sagittarius A* is a compact radio source at the Galactic center, powered byaccretion of fully ionized plasmas into a supermassive black hole. However, theradio emission cannot be produced through the thermal synchrotron process by agravitationally bounded flow. General relativisticmagneto-hydrodynamicalGRMHD simulations of black hole accretion show thatthere are strong unbounded outflows along the accretion. With the flowstructure around the black hole given by GRMHD simulations, we investigatewhether thermal synchrotron emission from these outflows may account for theobserved radio emission. We find that simulations producing relatively highvalues of plasma beta cannot produce the radio flux level without exceeding theX-ray upper limit set by Chandra observations through the bremsstrahlungprocess. The predicted radio spectrum is also harder than the observed spectrumboth for the one temperature thermal model and a simple nonthermal model with asingle power-law electron distribution. The electron temperature needs to belower than the gas temperature near the black hole to reproduce the observedradio spectrum. A more complete modeling of the radiation processes, includingthe general relativistic effects and transfer of polarized radiation, will givemore quantitative constraints on physical processes in Sgr A* with the currentmulti-wavelength, multi-epoch, and polarimetric observations of this source.



Autor: Kyle W. Martin, Siming Liu, Chris Fragile, Cong Yu, Chris L. Fryer

Fuente: https://arxiv.org/







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