2015/03/24 by M. Fukushima, Fukushima, M. · 1 citation
Computer Science · Physics and Astronomy · #Astrophysics and Cosmic Phenomena #Computational Physics and Python Applications #FOS: Physical sciences #High Energy Astrophysical Phenomena (astro-ph.HE) #Instrumentation and Methods for Astrophysics (astro-ph.IM) #Radio Astronomy Observations and Technology
paper · pdf · doi:10.48550/arxiv.1503.06961
openalex publication_date 2015/03/24 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
The Telescope Array (TA) is an experiment to observe Ultra-High Energy Cosmic Rays (UHECRs). TA's recent results, the energy spectrum and anisotropy based on the 6-year surface array data, and the primary composition obtained from the shower maximum Xmax are reported. The spectrum demonstrates a clear dip and cutoff. The shape of the spectrum is well described by the energy loss of extra-galactic protons interacting with the cosmic microwave background (CMB). Above the cutoff, a medium-scale (20 degrees radius) flux enhancement was observed near the Ursa-Major. A chance probability of creating this hotspot from the isotropic flux is 4.0 sigma. The measured Xmax is consistent with the primary being proton or light nuclei for energies 1018.2 eV - 1019.2 eV.