Magnetic flux density from the relative circular motion of stars and partially ionized gas in the Galaxy mid-plane vicinity

TL;DR

This paper proposes a simple model linking the relative circular motion of stars and gas in the Milky Way to magnetic fields of about 10 micro Gauss, offering a new method to estimate galactic magnetic fields.

Contribution

It introduces a model connecting stellar and gas rotation differences to magnetic field strength, providing a potential tool for magnetic field estimation in spiral galaxies.

Findings

Magnetic fields of order 10 micro Gauss are consistent with observed stellar and gas rotation differences.

A North-South asymmetry in gas rotation may be magnetic in origin.

The model aligns with observed magnetic field values in the Galaxy.

Abstract

Observations suggest a slower stellar rotation relative to gas rotation in the outer part of the Milky Way Galaxy. This difference could be attributed to an interaction with the interstellar magnetic field. In a simple model, fields of order 10 micro Gauss are then required, consistently with the observed values. This coincidence suggests a tool for estimating magnetic fields in spiral galaxies. A North-South asymmetry in the rotation of gas in the Galaxy could be of magnetic origin too.