Highlights from VERITAS on VHE gamma-ray sources in our Galaxy

Abstract

VERITAS is a major ground-based detector of very high energy (VHE, E >100GeV) gamma rays and cosmic rays. VERITAS consists of an array of four 12m-diameter atmospheric Cherenkov telescopes that has been fully operational since September 2007. VERITAS has detected many astrophysical sources of VHE gamma rays, including at least 17 VHE sources that are likely Galactic in origin. This paper describes some of the Galactic source highlights from VERITAS with an emphasis on those aspects that relate to the origin of cosmic rays. Specifically, topics include the VERITAS discovery of VHE emission from the Tycho and CTA 1 supernova remnants, the identification of HESS J0632+057 as a new VHE binary, a substantially improved view of the gamma-ray emission in the Cygnus OB1 region, and the recent remarkable discovery of VHE emission from the Crab pulsar. In 2009, VERITAS was upgraded by relocation of one of the telescopes, leading to a significant improvement in sensitivity. A program to further improve the performance of VERITAS, involving the upgrade of the telescope trigger systems and the telescope cameras, was completed in summer 2012. The upgrade has led to an improved sensitivity and a lower energy threshold for VERITAS, allowing it to perform deeper observations of known Galactic and extragalactic sources and to detect fainter and more distant sources.