144 research outputs found
Testing Lorentz invariance with neutrino bursts from supernova neutronization
Quantum-gravity (QG) effects might generate Lorentz invariance violation by
the interaction of energetic particles with the foamy structure of the
space-time. As a consequence, particles may not travel at the universal speed
of light. We propose to constrain Lorentz invariance violation for energetic
neutrinos exploiting the neutronization burst from the next galactic
supernova (SN). This prompt signal is expected to produce a sharp peak in the
SN light curve with a duration of ms. However presence of
energy-dependent Lorentz invariance violation would significantly spread out
the time structure of this signal. We find that the detection the SN
burst from a typical galactic explosion at kpc in a Mton-class water
Cerenkov detector, would be sensitive to a quantum-gravity mass scale GeV ( GeV) for the linear (quadratic) energy
dependence of Lorentz invariance violation. These limits are rather independent
of the neutrino mass hierarchy and whether the neutrino velocity is super or
subluminal.Comment: 4 pages, 3 figures, Revised version. Minor changes. Matches published
versio
Extragalactic Sources and Propagation of UHECRs
With the publicly available astrophysical simulation framework for
propagating extraterrestrial UHE particles, CRPropa 3, it is now possible to
study realistic UHECR source scenarios including deflections in Galactic and
extragalactic magnetic fields in an efficient way. Here we discuss three recent
studies that have already been done in that direction. The first one
investigates what can be expected in the case of maximum allowed intergalactic
magnetic fields. Here is shown that, even if voids contain strong magnetic
fields, deflections of protons with energies from
nearby sources might be small enough to allow for UHECR astronomy. The second
study looks into several scenarios with a smaller magnetization focusing on
large-scale anisotropies. Here is shown that the local source distribution can
have a more significant effect on the large-scale anisotropy than the EGMF
model. A significant dipole component could, for instance, be explained by a
dominant source within 5 Mpc distance. The third study looks into whether
UHECRs can come from local radio galaxies. If this is the case it is difficult
to reproduce the observed low level of anisotropy. Therefore is concluded that
the magnetic field strength in voids in the EGMF model used here is too low
and/or there are additional sources of UHECRs that were not taken into account
in these simulations.Comment: UHECR2016 conference proceedin
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