VERITAS Phase I: A Cherenkov Telescope Array For Gamma-Ray Astrophysics

Smithsonian Institution Astrophysical Observatory, Cambridge MA

Investigators

Abstract

AST 0234268 Weekes The Smithsonian Astrophysical Observatory will manage the construction of the Very Energetic Radiation Imaging Telescope Array System (VERITAS), an array of four 12m aperture telescopes for gamma-ray astronomy in the 50 GeV to 50 TeV energy range. These atmospheric Cherenkov telescopes will use the imaging concept developed by the Whipple Observatory Gamma-Ray Collaboration and used to detect the first galactic and extragalactic sources of TeV gamma-rays. VERITAS will achieve an order of magnitude better flux sensitivity than existing telescopes. It will be the only gamma-ray telescope array in the northern hemisphere and will complement the HESS and CANGAROO observatories in the southern hemisphere. Each VERITAS telescope will have an effective mirror area of 100 sq m (equivalent to a telescope of aperture ~12m) and a long focal length (12 m) with the optical design optimized for good angular resolution, a large field of view, and minimum wavefront distortion. Each telescope camera will have 499 pixels covering a 3.5 degree field of view with 0.15 degree resolution. VERITAS will have appreciable sensitivity at 80 GeV (where it will overlap with the next generation space telescopes) and at 10 TeV (where it will overlap with particle air shower detectors). With stereoscopic imaging, the array will achieve unprecedented angular resolution, energy resolution and background rejection over three decades of energy. The minimum detectable flux sensitivity will be 1% of the Crab Nebula at 200 GeV, a factor of 20 improvement over the most sensitive telescopes currently operating in this energy range. The primary scientific objectives of VERITAS will be the study of active galactic nuclei, supernova remnants, pulsars, the galactic plane, and gamma-ray bursts; in addition a sky survey will be made to search for new astrophysical sources. VERITAS will also explore new physics in areas such as neutralino annihilation, quantum gravity and primordial black hole evaporation. VERITAS will effectively complement GLAST, the next major high energy gamma-ray telescope in space; they will overlap in the 50 GeV to 300 GeV energy range allowing important cross correlations. Together, VERITAS and GLAST may solve the problem of the origin of the cosmic radiation as well as probing fundamental questions in physics and cosmology. The VERITAS Collaboration consists of groups from ten institutions: Iowa State University, McGill University, National University of Ireland, Purdue University, Smithsonian Astrophysical Observatory, University of California at Los Angeles, University of Chicago, University of Leeds, University of Utah, and Washington University. The array will be built at a dark site on Kitt Peak in southern Arizona. VERITAS is a unique scientific endeavor which offers unusual opportunities for education and outreach. Because the project falls in the interface between high energy physics and astronomy, between particle astrophysics and high energy astrophysics, it is inherently multi-disciplinary. The VERITAS Outreach program will capitalize on the experience of the Smithsonian Astrophysical Observatory, as well as that of the university groups involved in VERITAS. The project is funded by the Department of Energy and the National Science Foundation, in approximately equal shares. Within NSF, the funding partners are Division of Astronomical Sciences, Division of Physics, and Office of Multidisciplinary Activities in the Directorate for Mathematical and Physical Sciences. ***