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arXiv · 1008.2658

The Fermi Bubbles: Giant, Multi-Billion-Year-Old Reservoirs of Galactic Center Cosmic Rays

Roland M. Crocker·Felix Aharonian
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Abstract

Recently evidence has emerged for enormous features in the gamma-ray sky observed by the Fermi-LAT instrument: bilateral `bubbles' of emission centered on the core of the Galaxy and extending to around 10 kpc above and below the Galactic plane. These structures are coincident with a non-thermal microwave `haze' found in WMAP data and an extended region of X-ray emission detected by ROSAT. The bubbles' gamma-ray emission is characterised by a hard and relatively uniform spectrum, relatively uniform intensity, and an overall luminosity ~4 x 10^37 erg/s, around one order of magnitude larger than their microwave luminosity while more than order of magnitude less than their X-ray luminosity. Here we show that the bubbles are naturally explained as due to a population of relic cosmic ray protons and heavier ions injected by processes associated with extremely long timescale (>~8 Gyr) and high areal density star-formation in the Galactic center.

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Roland M. Crocker, Felix Aharonian. 2011-02-14. The Fermi Bubbles: Giant, Multi-Billion-Year-Old Reservoirs of Galactic Center Cosmic Rays. https://doi.org/10.1103/physrevlett.106.101102

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