Tuesday 18 October 2016
to 14:30 at
Giacomo Vianello (Stanford University)
Gamma-Ray Bursts are center stage in the new era of multi-messenger astronomy, as their nature is probed through photons, gravitational waves (GW), neutrinos and cosmic rays. Discovered thanks to their powerful multi-wavelength electromagnetic signal, they have been linked to the explosion of very massive stars ("long GRBs"), or to the coalescence of compact objects ("short GRBs") which also produce a GW signal. GRBs are also believed to be efficient particle accelerators, as required by the observation of high-energy photons up to ~100 GeV. Therefore, quite naturally, they have been proposed as possible sources of the mysterious ultra-high-energy cosmic rays (UHECRs), with energies above 10^18 eV. However, some of the current models that simultaneously produce high electromagnetic fluxes and high-energy cosmic rays necessarily produce neutrinos as well, with a flux which appears to violate the limits recently set by the IceCube detector. I will review the observational features of GRBs as multi-messenger sources, as well as their link to theoretical models.
(host Michael Burgess)