Astroparticle Physics Seminar

Disentangling the gamma-ray emission from the Galactic bulge: Status and Prospects

by Prof. Christoph Weniger (GRAPPA and University of Amsterdam)

Thursday, 19 April 2018 from to (Europe/Berlin)
at 313
Description
The Fermi Large Area Telescope has during its almost 10 years of mission time revolutionized our understanding of the gamma-ray sky. It enabled, e.g., the discovery of the Fermi bubbles, a surprisingly large number of gamma-ray emitting millisecond pulsars, dark gas in the Milky Way disk, and an excess of GeV photons from the Galactic bulge and center. The latter, often dubbed "Fermi GeV excess", caused a lot of excitement since it is compatible with a self-annihilation signal from WIMP dark matter. Circumstantial evidence points now however in another direction, namely that the excess is caused by the combined emission of thousands of unresolved millisecond pulsars in the Galactic bulge. Furthermore, additional gamma-ray emission from star formation, from the activity of the central supermassive black hole, and gamma-ray emission associated with the Fermi bubbles can potentially play an important role for the bulge emission. I will present the current state of the discussion, results from the new analysis code SkyFACT that support the millisecond pulsar interpretation of the Fermi GeV excess, and plans for the future to further disentangle the various contributions to the gamma-ray emission from the Galactic bulge and center. A better understanding of this emission will shed further light on the history and activity of the inner Galaxy.