A new model of the galactic magnetic field

Ronnie Jansson, Glennys R. Farrar

    Research output: Contribution to journalArticle

    Abstract

    A new, much-improved model of the Galactic magnetic field (GMF) is presented. We use the WMAP7 Galactic synchrotron emission map and more than 40,000 extragalactic rotation measures to constrain the parameters of the GMF model, which is substantially generalized compared with earlier work to now include an out-of-plane component (as suggested by observations of external galaxies) and striated-random fields (motivated by theoretical considerations). The new model provides a greatly improved fit to observations. Consistent with our earlier analyses, the best-fit model has a disk field and an extended halo field. Our new analysis reveals the presence of a large, out-of-plane component of the GMF; as a result, the polarized synchrotron emission of our Galaxy seen by an edge-on observer is predicted to look intriguingly similar to what has been observed in external edge-on galaxies. We find evidence that the cosmic-ray electron density is significantly larger than given by GALPROP or else that there is a widespread striated component to the GMF.

    Original languageEnglish (US)
    Article number14
    JournalAstrophysical Journal
    Volume757
    Issue number1
    DOIs
    StatePublished - 2012

    Fingerprint

    interstellar magnetic fields
    magnetic field
    galaxies
    synchrotrons
    cosmic ray
    electron density
    cosmic rays
    halos

    Keywords

    • Galaxy: general
    • Galaxy: structure
    • ISM: magnetic fields

    ASJC Scopus subject areas

    • Space and Planetary Science
    • Astronomy and Astrophysics

    Cite this

    A new model of the galactic magnetic field. / Jansson, Ronnie; Farrar, Glennys R.

    In: Astrophysical Journal, Vol. 757, No. 1, 14, 2012.

    Research output: Contribution to journalArticle

    Jansson, Ronnie ; Farrar, Glennys R. / A new model of the galactic magnetic field. In: Astrophysical Journal. 2012 ; Vol. 757, No. 1.
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