The Galactic Haze/Bubbles: Our Ringside Seat for Energetic Phenomena in the Centers of Galaxies

Greg Dobler

November 17, 2011

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Abstract: Recently we have discovered an enormous feature in full sky maps from the Fermi Gamma-Ray Space Telescope. The emission is centered on the Galactic center, is elongated in latitude by a factor of roughly two, and extends a full +/- 10 kpc away from the Galactic plane making it the second largest structure in the Galaxy after the Galactic disk. This emission is generated by a cloud of electrons with a very hard spectrum inverse Compton scattering low energy photons up to Fermi energies. It has come to be known as the “Fermi Haze” or “Fermi Bubbles” and represents a unique opportunity to get a close up view of energetic phenomena that occur in the centers of galaxies. I will go through the observational evidence for the haze/bubbles at multiple wavelengths and describe the leading theoretical contenders for the origin of this emission concentrating on two particularly attractive possibilities: an accretion driven jet-blown bubble and co-annihilation of particle dark matter in the Galactic halo.