Magnetic Field Structure near the Galactic Plane

TL;DR

This paper maps the Galactic magnetic field near the plane, confirming reversals in spiral arms and revealing asymmetry in the Sagittarius arm, challenging existing symmetric models.

Contribution

It provides new two-color magnetic field maps in Galactic coordinates and identifies asymmetry in the Sagittarius spiral arm's magnetic field.

Findings

Magnetic field reversals occur in neighboring spiral arms.

The Sagittarius arm's magnetic field is asymmetric, mainly in the Northern hemisphere.

Discrepancies with standard symmetric magnetic field models.

Abstract

We bring the two color maps for the plane component magnetic field of our Galaxy in coordinates of (R;l) and (DM;l). It was shown that magnetic field has reversals of the direction in neighbor spiral arms, in agreement with known models for the Galactic magnetic field. For the Sagittarius spiral arm region there is, however, some disagreement with standard magnetic field models. The major discrepancy is the fact that in the Sagittarius arm region the magnetic field in Southern hemisphere of the Galaxy, have opposite direction to the field of the Northern hemisphere. We think that the Sagittarius spiral arm, at last the magnetic spiral arm in this region is not symmetric to the Galactic plane, and is located mainly in Northern hemisphere.