The Large Scale Anisotropy of TeV Cosmic-Rays as Observed with Milagro

The Milagro observatory is a water Cherenkov detector located in the Jemez mountains outside of Los Alamos, New Mexico. With a high duty cycle and large field-of-view, Milagro has high sensitivity for measuring the large scale cosmic-ray anisotropy at TeV energies. We present a two-dimensional map of the sidereal anisotropy generated by a harmonic analysis of the data collected over a seven year period consisting of more than 160 billion events. We observe an anisotropy with a magnitude on the order of 0.1\% for cosmic rays with a median energy of 3 TeV. The dominant feature is a deficit region of mean depth ($-2.5 \pm 0.046$ stat. $\pm 0.19$ syst.)$\times10^{-3}$ in the direction of the Galactic North Pole with a range in declination of -10 to 45 degrees and 150 to 225 degrees in right ascension. We also present evidence of an increase in the magnitude of this deficit region over time as well as a weakening of the signal for energies above 20 TeV.