Wednesday, April 24, 2013

1304.6137 (Brian C. Lacki)

The Fermi Bubbles as Starburst Wind Termination Shocks    [PDF]

Brian C. Lacki
The enhanced star formation in the inner 100 pc of the Galaxy launches a superwind, reaching ~1600 km/s for M82-like parameters. The ram pressure of the wind is very low compared to more powerful starburst winds. I show that halo gas stops the wind a few kpc from the Galactic Center. I argue that the termination shock accelerates cosmic rays, and that the resulting Inverse Compton gamma-rays are visible as the Fermi Bubbles. The Bubbles are thus wind bubbles, which the starburst can inflate within 10 Myr. They remain in steady state as long as the starburst lasts. The shock may accelerate PeV electrons and ultra-high energy protons. The Bubbles may be analogs of galactic wind termination shocks in the intergalactic medium. I discuss the advantages and problems of this model.
View original: http://arxiv.org/abs/1304.6137

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