Special Astronomy & Astrophysics Seminar: Multimessenger studies of extreme cosmic particle accelerators

Abstract:

The term “multimessenger” means simply observing the universe with photons, neutrinos, cosmic rays and gravitational waves. But what can we really learn about the radiation sources and particle accelerators?

And in particular how?

In my talk I will focus on the recent observations of the high-energy sky, i.e. the sources of neutrinos in IceCube, of Ultra-High Energy Cosmic Rays in the Pierre Auger Observatory or the Telescope Array and the gamma-rays in Fermi and the Cherenkov telescopes. The presence of high-energy neutrinos implies that baryons are present in some of the sources, they are accelerated to very high energies (at least ~20*5 = 100 PeV ) and that these nuclei either interact with gas or photons locally nearby the accelerator. The discrimination between the candidate source classes, for example Gamma-Ray Bursts, Tidal Disruption Events or Blazars, can happen in two ways: via the analysis of diffuse fluxes from entire source populations or by studying individual sources. I will discuss the recent progress using both methods including very promising new neutrino point-source candidates.

Seminar Organizer: Prof. Sara Beck