Relativistic Radiative Hydrodynamics Calculation of Accretion Flow into Supermassive Black Hole

Accretion;Black hole;Supermassive black hole;Synchrotron emission;Sagittarius A*;Radiative transfer

Leung, Po Kin

关键词: Accretion;    Black hole;    Supermassive black hole;    Synchrotron emission;    Sagittarius A*;    Radiative transfer;   

Others  :  https://www.ideals.illinois.edu/bitstream/handle/2142/18532/Leung_PoKin.pdf?sequence=1&isAllowed=y

美国|英语

来源: The Illinois Digital Environment for Access to Learning and Scholarship

【 摘 要 】

The compact radio source Sagittarius A* (Sgr A*) is the nearest and most-intensively-studied supermassive black hole candidate. With a broadband spectrum which likely requires several emission mechanisms for explanation, and structure of innermost accretion flow not yet well constrained, the understanding of accretion into Sgr A* demands advances in both theories and computational calculation.To increase the understanding of Sgr A* in particular, and low-luminosity active galactic nuclei in general, we perform relativistic radiative transfer (RT) calculation with general relativistic magnetohydrodynamic (GRMHD) simulation of accretion flow simulation.We are able to use the models to constrain observational parameters of Sgr A*.We also compute the synchrotron emissivity and absorptivity from first principles, in order to verify improved approximate equations for the RT calculation.The code can handle a wide range of electron distributions, therefore the application is not limited to accretion disk simulation.In order to explain a feature in the observed flaring spectrum, we add nonthermal component to the electron distribution.We then perform relativistic Monte Carlo RT calculation of the disk model, and show that asmall amount of power-law electron is enough to modify the spectral slope.Finally, we describe a recipe for performing relativistic polarized RT, which would allow a further study to constrain model parameters with polarization observations from Sgr A*.