Ultra-high energy cosmic-ray spectra measured by the Telescope Array experiment from hybrid observations

摘要

The three fluorescence detector (FD) stations of the Telescope Array (TA) experiment have been taking datasince the end of 2007. In this paper, we report the spectrum from hybrid events recorded from the Black Rock Mesa(BR) and Long Ridge (LR) sites in coincidence with the surface array. The hybrid events from the new FADC-basedcameras and 6 m2mirrors at BRM and LR sites give the best geometrical and energy resolution as well as the mostreliable aperture calculation. The MD site was built exclusively from refurbished telescopes from the HiRes-1 site of theHigh Resolution Fly's Eye (HiRes) experiment. The latter was the first to observe the Greisen-Zatsepin-K'uzmin (GZK)prediction of suppressed flux above 6 × 1019eV. An updated MD monocular spectrum is included in this paper, while thehybrid MD analysis will be reported in another paper