THE GALACTIC MAGNETIC FIELD

Abstract

With this Letter, we complete our model of the Galactic magnetic field (GMF),\nby using the WMAP7 22 GHz total synchrotron intensity map and our earlier\nresults to obtain a 13-parameter model of the Galactic random field, and to\ndetermine the strength of the striated random field. In combination with our\n22-parameter description of the regular GMF, we obtain a very good fit to more\nthan forty thousand extragalactic Faraday Rotation Measures (RMs) and the WMAP7\n22 GHz polarized and total intensity synchrotron emission maps. The data calls\nfor a striated component to the random field whose orientation is aligned with\nthe regular field, having zero mean and rms strength ~20% larger than the\nregular field. A noteworthy feature of the new model is that the regular field\nhas a significant out-of-plane component, which had not been considered\nearlier. The new GMF model gives a much better description of the totality of\ndata than previous models in the literature.\n