The Nature of Linearly Polarized Millimeter and Sub-millimeter Emission in Sagittarius A*

TL;DR

This paper investigates the origin and properties of linearly polarized millimeter and sub-millimeter emission in Sagittarius A*, linking observations with MHD simulations to constrain the accretion disk model near the black hole.

Contribution

It combines observational data with MHD simulations to provide new constraints on the electron heating, disk inclination, and magnetic field structure in Sagittarius A*.

Findings

Polarization sensitive to electron heating rate and disk inclination.

Intrinsic polarization aligned with the disk's rotation axis.

Spectral and polarization data tightly constrain accretion disk models.

Abstract

The linearly polarized millimeter and sub-millimeter emission in Sagittarius A* is produced within 10 Schwarzschild radii of the supermassive black hole at the Galactic Center and may originate from a hot magnetized accretion disk, where electrons are heated efficiently by turbulent plasma waves. In such a scenario, the flux density and polarization are very sensitive to the electron heating rate and the inclination angle of disk, respectively, and the major axis of the sub-millimeter intrinsic polarization, which is aligned with the rotation axis of the disk, is perpendicular to the major axis of the polarized near-infrared emission. In combination with MHD simulations, which study the properties of the magnetic field and viscous stresses, the current spectral and polarization measurements give tight constraints on the model parameters. Simultaneous observations will be able to test the model.