The Galactic Magnetic Field

TL;DR

This paper presents a comprehensive 13-parameter model of the Galactic magnetic field, incorporating regular, random, and striated components, fitting extensive observational data for improved accuracy.

Contribution

The study introduces a novel, detailed GMF model with a significant out-of-plane component and a striated field aligned with the regular field, enhancing previous models.

Findings

The model fits over forty thousand extragalactic RMs and WMAP7 data.

The striated field has zero mean and is ~20% stronger than the regular field.

The regular field includes a significant out-of-plane component.

Abstract

With this Letter, we complete our model of the Galactic magnetic field (GMF), by using the WMAP7 22 GHz total synchrotron intensity map and our earlier results to obtain a 13-parameter model of the Galactic random field, and to determine the strength of the striated random field. In combination with our 22-parameter description of the regular GMF, we obtain a very good fit to more than forty thousand extragalactic Faraday Rotation Measures (RMs) and the WMAP7 22 GHz polarized and total intensity synchrotron emission maps. The data calls for a striated component to the random field whose orientation is aligned with the regular field, having zero mean and rms strength ~20% larger than the regular field. A noteworthy feature of the new model is that the regular field has a significant out-of-plane component, which had not been considered earlier. The new GMF model gives a much better description of the totality of data than previous models in the literature.