Revisiting the cosmic ray-neutrino connection in gamma-ray bursts
por
Mauricio Bustamante
(DESY Zeuthen and Universität Würzburg (Germany))
→
Europe/Madrid
Seminar Room 1.1.1 (IFIC)
Seminar Room 1.1.1
IFIC
Descripción
Fifty years after the discovery of ultra-high energy cosmic rays (UHECRs), their origin still puzzles us. Among the most likely potential candidates are gamma-ray bursts (GRBs): short, extremely luminous flashes of gamma-rays, so far detected as having occurred only outside the Galaxy. In them, intense magnetic fields are believed to exist that would accelerate magnetically-confined protons or nuclei to the high energies (<~ 10^21 eV) that are necessary to explain the UHECR observations. These UHE protons interact with the photons in the source to create neutrinos of comparable energy, the detection of which would constitute persuasive evidence of the occurrence of hadronic acceleration in the sources. The IceCube neutrino telescope has now reached sensitivities that are able to start testing these predictions; the latest analysis, in fact, disfavours the basic model of GRB neutrino emission. We will present here an improved numerical calculation of the neutrino flux from GRBs (NeuCosmA) which relieves this tension and which has now been used by the ANTARES telescope for its GRB neutrino search. Furthermore, we introduce a generalised model of UHECR emission from GRBs that allows for the imperfect magnetic confinement of the protons, which modifies both the UHECR and neutrino fluxes. Finally, within a joint model of UHE proton and neutrino emission and propagation, we show that by using the current UHECR observations by giant air shower detectors and the IceCube upper bounds on the UHE neutrino flux, we are already able to constrain the properties that GRBs should have if they are to be the sources of the most energetic particles observed.