Observation of Anisotropy of TeV Cosmic Rays with Two Years of HAWC
2018
After two years of operation, the High-Altitude Water Cherenkov (HAWC) Observatory has analyzed the TeV
cosmic-raysky over an energy range between $2.0$ and $72.8$ TeV. The HAWC detector is a ground-based
air-showerarray located at high altitude in the state of Puebla, Mexico. Using 300 light-tight water tanks, it collects the Cherenkov light from the particles of extensive
air showersfrom primary gamma rays and
cosmic rays. This detection method allows for uninterrupted observation of the entire overhead sky (2~sr instantaneous, 8.5~sr integrated) in the energy range from a few TeV to hundreds of TeV. Like other detectors in the northern and southern hemisphere, HAWC observes an energy-dependent anisotropy in the arrival direction distribution of
cosmic rays. The observed
cosmic-rayanisotropy is dominated by a dipole moment with phase $\alpha\approx40^{\circ}$ and amplitude that slowly rises in relative intensity from $8\times10^{-4}$ at 2 TeV to $14\times10^{-4}$ around 30.3 TeV, above which the dipole decreases in strength. A significant large-scale ($>60^{\circ}$ in angular extent) signal is also observed in the quadrupole and octupole moments, and significant small-scale features are also present, with locations and shapes consistent with previous observations. Compared to previous measurements in this energy range, the HAWC
cosmic-raysky maps improve on the energy resolution and fit precision of the anisotropy. These data can be used in an effort to better constrain local
cosmic-rayaccelerators and the intervening magnetic fields.
Keywords:
-
Correction
-
Source
-
Cite
-
Save
62
References
22
Citations
NaN
KQI