The Fermi haze: A Gamma-ray counterpart to the microwave haze

Gregory Dobler, Douglas P. Finkbeiner, Ilias Cholis, Tracy Slatyer, Neal Weiner

    Research output: Contribution to journalArticlepeer-review


    The Fermi Gamma-ray Space Telescope reveals a diffuse inverse Compton (IC) signal in the inner Galaxy with a similar spatial morphology to the microwave haze observed by WMAP, supporting the synchrotron interpretation of the microwave signal. Using spatial templates, we regress out π0 gammas, as well as IC and bremsstrahlung components associated with known soft-synchrotron counterparts. We find a significant gamma-ray excess toward the Galactic center with a spectrum that is significantly harder than other sky components and is most consistent with IC from a hard population of electrons. The morphology and spectrum are consistent with it being the IC counterpart to the electrons which generate the microwave haze seen at WMAP frequencies. In addition, the implied electron spectrum is hard; electrons accelerated in supernova shocks in the disk which then diffuse a few kpc to the haze region would have a softer spectrum. We describe the full-sky Fermi maps used in this analysis and make them available for download.

    Original languageEnglish (US)
    Pages (from-to)825-842
    Number of pages18
    JournalAstrophysical Journal
    Issue number2
    StatePublished - 2010


    • gamma rays: ISM
    • gamma rays: general

    ASJC Scopus subject areas

    • Astronomy and Astrophysics
    • Space and Planetary Science


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