NICHE: Air-Cherenkov observation at the TA site

Abstract

The Non-Imaging CHErenkov (NICHE) Array has been deployed at the Telescope Array Middle Drum site, and has been collecting data. We see many coincidences with TALE fluorescence mirror events, establishing hybrid imaging/non-imaging air-Cherenkov observation of cosmic ray air showers. We have verified the TALE Profile-Constrained Geometry Fit of Cherenkov events at the 3° level. We have performed hybrid timing fits between NICHE and TALE and have established that the growth in the FWHM of the NICHE signal with the distance of the shower core depends on the height of the shower maximum.