EXTREMELY HIGH ENERGY (E larger 10^{20} eV) COSMIC RAYS: OBSERVATIONS AND POTENTIAL SOURCES

Discussion timeslot (ZOOM-Meeting): 16. July 2021 - 18:00
ZOOM-Meeting URL: https://icrc2021.desy.de/pf_access_abstracts
Corresponding Session: https://icrc2021-venue.desy.de/channel/Presenter-Forum-1-Evening-All-Categories/48
Abstract:
'The search for sources of ultra-high energy cosmic rays (UHECR, $E > 10^{18}$ eV) remains one of the advanced tasks in high energy astrophysics. The observed high degree of isotropy of the UHECR intensity due to impact of  extragalactic and Galactic magnetic fields, together with a significant uncertainty in their chemical composition (atomic masses) due to indirect detection, don’t allow to link observed events to their sources and to establish acceleration mechanisms. To reduce the effects of deflection in magnetic fields and composition  uncertainty, we consider the most energetic tail of UHECR - rare  extremely high energy cosmic  rays (EHECR, $E>10^{20}$ eV). Strongly energy-depended  loss length of UHECR - GZK-effect at $E>10^{19.5}$ eV further reduces the  energy loss horizon  of $E>10^{20.5}$ eV EHECR  to a few Mpc level, favoring only protons and Fe group nuclei with $sim$10 Mpc level. Event-by-event reconstruction of EHECR trajectories in Galactic and extragalactic magnetic fields opens up a possibility to discover their close to us  sources. We collect the existing data of EHECR detections  at Fly's Eye (1 event), Pierre Auger Observatory (PAO, 14 events after $k=1.2$ energy calibraion ) and Telescope Array (TA, 22 events) and identify their  potential sources at distances, restricted by energy loss horizon to 30-50 Mpc, among extragalactic (active galaxy nuclei, starburst galaxies) and Galactic  (magnetars) candidates. The most promising candidates are Hypernovae with millisecond pulsar/magnetar, giant flares of magnetars, Kilonovae (NS-NS mergers), tidal disruption events etc. accompanied by (mildly) relativistic jets with close to the Earth directions.'

Authors: Roman Hnatyk | Vadym Voitsekhovskyi
Indico-ID: 581
Proceeding URL: https://pos.sissa.it/395/464