Constraining the Accretion Flow in Sgr A* by GR Dynamical and Radiative Modeling

TL;DR

This paper combines 3D GRMHD simulations with GR polarized radiative transfer to model the accretion flow in Sagittarius A*, fitting observational data to constrain black hole parameters.

Contribution

It introduces a comprehensive framework integrating dynamical accretion models with polarized radiative transfer for Sgr A*.

Findings

Best fit for spin a=0.7 and inclination 0.6 matches sub-mm flux and polarization.

Provides precise fitting formulas for Faraday effects in thermal plasma.

Models magnetic field and flow geometry based on averaged 3D GRMHD simulations.

Abstract

We present the combination of dynamical accretion model based on 3D GRMHD simulations and general relativistic (GR) polarized radiative transfer. We write down the formalism of and perform the GR ray-tracing of cyclo-synchrotron radiation through the model of accretion flow in Sagittarius A*. GR polarimetric imaging is presented as well as the results for spectrum for a probable set of spins and orientations. Precise fitting formulae for Faraday rotation and Faraday conversion coefficients are employed for thermal plasma. The axisymmetic flow pattern and the magnetic field geometry correspond to averaged 3D GRMHD simulations near the black hole, whereas the analytic model was used far from the black hole. The density scaling is found by fitting the sub-mm flux. Spin $a=0.7$ and inclination angle $\theta=0.6$ produce the best fit to sub-mm flux and linear polarization fraction.