Expected number of Extensive Air Showers observable by EUSO-SPB

Abstract

EUSO-SPB (Extreme Universe Space Observatory-Super Pressure Balloon) is the first pathfinder mission of the JEM-EUSO program aiming at the detection of the fluorescence light emitted by Extensive Air Shower (EAS) produced by cosmic ray particles in the atmosphere. EUSO-SPB has flown in Spring 2017 from the Wanaka base in New Zealand on board a NASA Super Pressure Balloon planning to reach up to a 100 days of flight, giving, therefore, the opportunity to observe for the first time a bunch of cosmic ray events with the fluorescence technique from the edge of space. By means of the ESAF (EUSO Simulation and Analysis Framework) package, which is one of the official simulation tools to study the performance of the different pathfinder missions of the JEM-EUSO program, prior to flight, extensive simulations have been carried out to determine the expected number of detectable events as a function of several parameters related to the detector performance itself (i.e. trigger logic, optics and electronics efficiency), to the different environmental conditions (i.e. night-glow level, presence of clouds at different heights with variable optical depth) as well as to the launch season and duration of the flight. The main results of these simulation studies are presented.

On the Common Origin of Cosmic Rays across the Ankle and Diffuse Neutrinos at the Highest Energies from Low-luminosity Gamma-Ray Bursts

“…We inject a nuclear composition which is found to be reasonable in the jet of GRB progenitors (Woosley & Heger 2006;Zhang et al 2018), and we include the transition to the next population (at lower energies). As an important ingredient, it was noted in Unger et al (2015) in a generic model and in Globus et al (2015b); Biehl et al (2018a) for GRBs that the nuclear cascade also controls the production of nucleons below the change of the slope in the measured CR energy spectrum, called the "ankle" at ∼ 5 · 10 18 eV (Fenu, F. et al 2017), i.e., spectrum and composition may be described in a much larger energy range across the ankle. Our analysis is based on a combined source-propagation model, which means that we include the interactions of the injected nuclei in the source in addition to the UHECR propagation, whereas a propagation-only model starts off at the interface between source and extragalactic space.…”

EUSO-SPB1 Mission and Science

“…The number of cosmic ray air showers expected has been derived from two independent simulations [34] and [30,35]. A simulated energy distribution, based on a longer duration SPB flight than was realized, is shown in Fig.…”

Search for the footprints of new physics with laboratory and cosmic neutrinos

“…Future neutrino detectors are being planned or constructed: IceCube-Gen 2, 43 the Askaryan effect detectors ARA 44 and ARIANNA, 45 and space-based telescopes such as OWL, 46 EUSO, 47 and a more advanced OWL-type instrument called POEMMA. They will provide more sensitive tests of LIV.…”