NBIA Seminar: Christoph Weniger

New methods to search for particle dark matter signals in the sky

Dark matter might be not completely dark. This is suggested by a number of theoretical models for particle dark matter, which predict that dark matter particles can self-annihilate or decay, giving rise to potentially detectable signals in astronomical gamma-ray, neutrino and cosmic-ray observations. After summarizing the possible experimental signatures, I will discuss in what ways dark matter signals could be identified on top of astrophysical backgrounds. I will focus on the well-known `Fermi GeV excess', an excess of GeV photons from the Galactic bulge and center that resembles remarkably well a dark matter signal. It was first identified seven years ago in data of the Fermi Large Area Telescope, and its origin is still one of the most puzzling open questions in gamma-ray astronomy. We developed new data analysis techniques, including wavelet fluctuation analyses and high-dimensional multi-linear regression, that provide fresh insights on its possible origin. The most likely astrophysical explanation is the combined emission of thousands of undetected millisecond pulsars in the Galactic bulge. Our planned mid-latitude survey with MeerKAT has the potential to clear up the situation in the next few years. I will close with an outlook on anticipated developments in indirect dark matter searches.