HAWC Response to Lighting Activity

Abstract:

The High Altitude Water Cherenkov (HAWC) observatory is being constructed at the Sierra Negra volcano (4100 m a.s.l.) in Mexico. HAWC’s primary purpose is the study of both: galactic and extra-galactic sources of high energy gamma rays. HAWC will consist of 300 large water Cherenkov detectors (WCD), each instrumented with 4 photo-multipliers (PMTs). The Data taking has already started while construction continues, with the completion projected for late 2014. The HAWC scaler system records the rates of individual PMTs giving the opportunity of study relatively low energy transients as solar energetic particles and the solar modulation of galactic cosmic rays. In this work, we present the observations of scaler rate enhancements associated with lightning activity observed close to HAWC (i. e. at high altitude). In particular, we present the time and space coincidence of the lighting strikes and the scaler enhancements and our preliminary speculations on the origin of the detector response to the lighting activity.