Ultra-high-energy-cosmic-ray hot spots from tidal disruption events
  We consider the possibility that tidal disruption events (TDEs) caused by
supermassive black holes (SMBHs) in nearby galaxies can account for the
ultra-high-energy cosmic-ray (UHECR) hotspot reported recently by the Telescope
Array (TA) and the warm spot by Pierre Auger Observatory (PAO). We describe the
expected cosmic-ray signal from a TDE and derive the constraints set by the
timescale for dispersion due to intergalactic magnetic fields and the accretion
time of the SMBH. We find that TDEs in M82 can explain the hotspot detected by
the TA regardless of whether the UHECRs are composed of protons or heavier
nuclei. We then check for consistency of the hot and warm spots from M82 and
Cen A with the full-sky isotropic signal from all SMBHs within the GZK radius.
This analysis applies to any scenario in which the hot/warm spots are real and
due to M82 and Cen A, regardless of whether TDEs are the source of UHECRs. We
find that the isotropic flux implied by the luminosity density inferred from
M82 and Cen A is bigger than that observed by roughly an order of magnitude,
but we provide several possible explanations, including the possibility of a
local overdensity and the possibility of intermediate-mass nuclei in UHECRs, to
resolve the tension.
