Inflow-Outflow Model with Conduction and Self-Consistent Feeding for Sgr A*

TL;DR

This paper introduces a comprehensive two-temperature inflow-outflow model for Sgr A* that incorporates self-consistent feeding, conduction, and relativistic effects, successfully fitting multiple observational data sets and revealing the central X-ray source.

Contribution

It presents a novel, self-consistent model of accretion onto Sgr A* that integrates stellar wind feeding, conduction, and relativistic effects, fitting diverse observational data.

Findings

Accretion rate limited to <1% of Bondi rate due to conduction.

Successfully fits X-ray surface brightness and infers central point source luminosity.

Achieves consistent modeling of radio and X-ray observations across radii.

Abstract

We propose a two-temperature radial inflow-outflow model near Sgr A* with self-consistent feeding and conduction. Stellar winds from individual stars are considered to find the rates of mass injection and energy injection. These source terms help to partially eliminate the boundary conditions on the inflow. Electron thermal conduction is crucial for inhibiting the accretion. Energy diffuses out from several gravitational radii, unbinding more gas at several arcseconds and limiting the accretion rate to <1% of Bondi rate. We successfully fit the X-Ray surface brightness profile found from the extensive Chandra observations and reveal the X-Ray point source in the center. The super-resolution technique allows us to infer the presence and estimate the unabsorbed luminosity $L\approx4\cdot10^{32}{\rm erg s^{-1}}$ of the point source. The employed relativistic heat capacity and direct heating of electrons naturally lead to low electron temperature $T_e\approx 4\cdot10^{10}$ K near the black hole. Within the same model we fit 86 GHz optically thick emission and obtain the order of magnitude agreement of Faraday rotation measure, thus achieving a single accretion model suitable at all radii.