Cosmic Ray Observations at the TeV Scale with the HAWC Observatory

07.02.2018 11:15 – 12:15

Measurements of cosmic rays at TeV energies provide important probes to understanding the nature and distribution of galactic acceleration sites as well as the interstellar environment in which cosmic-ray particles propagate. Below ~10 TeV, direct detection experiments provide the most detailed measurements of the primary particle spectrum, whereas ground-based air-shower arrays typically access energies above ~100 TeV and can measure the anisotropy of the cosmic ray arrival distribution. With its high duty cycle and large field of view (~2 sr), the High-Altitude Water Cherenkov (HAWC) Observatory, an air-shower array located near Puebla, Mexico, continuously surveys the Northern cosmic ray sky at very high energies (100 GeV-1 PeV). We report on the all-particle cosmic ray energy spectrum from 10-500 TeV measured with a selection of 8.4 x 109 HAWC events, including evidence of a spectral break near 46 TeV. The measured spectrum exhibits agreement within systematic uncertainties with various experiments demonstrating that HAWC can bridge the energy region between direct detection and air-shower array techniques. With a large data set (12.3 x 1010 events) obtained from two years of continuous observation and a new statistical method, we also present HAWC results of the cosmic-ray anisotropy from 2-73 TeV, confirming the presence of previously observed energy-dependent angular features on both large and small scales.

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Bâtiment: Ecole de Physique

Grand Auditoire A
24, quai Ernest-Ansermet

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