TeV Observations of Markarian 501 with the Milagrito Water Cherenkov Detector

Abstract

The Milagrito water Cherenkov detector near Los Alamos, New Mexico, operated as a sky monitor at energies of a few TeV between February 1997 and May 1998 including the period of the strong, long-lasting 1997 flare of Markarian 501. Milagrito served as a test run for the full Milagro detector. An event excess with a significance of 3.7 sigma from Markarian 501 was observed, in agreement with expectations.

10 pages, 3 figures (figure 2 in color). accepted for publication in ApJ Letters