201 James Fletcher Bldg.115 South 1400 East

Salt Lake City, UT 84112-0830(801) 581-6901

www.physics.utah.eduwww.astro.utah.edu

Dept of Physics & AstronomyUniversity of Utah

Experimental High Energy

Physics & Astrophysics

The University of Utah has a long standing tra-dition of excel-lence in cosmic ray research, extending back to the Park City mine experi-ments of the late 1960’s led by the late Prof. Jack Keuffel. This observato-ry searched for astrophysical sources of high energy neutrinos as well as phe-

nomenological aspects of cosmic ray physics.

Since this experiment, the University of Utah has hosted numerous experimental astrophysics pro-grams, including the Fly’s Eye Experiment (1976-1992), the Utah UHE surface array (1986-1990), CASA-MIA (Chicago Air Shower Array and Michigan muon Array), DICE (Dual Imaging Cherenkov Exper-iment), and BLANCA (Broad Lateral Non-imaging Cherenkov Array. Utah faculty have been involved with the design, construction, and operation of a series of next-generation instruments, including HiRes (the High Resolution Fly’s Eye, 1990-2006), Telescope Array, the Pierre Auger Cosmic Ray Ob-servatory, the VERITAS gamma ray observatory, the Milagro gamma ray observatory, the MAGPIE bal-loon experiment, and the CGRO, AMS, and GLAST satellite experiments.

Observatories

Gamma Ray Astronomy/VERITASwww.physics.utah.edu/gammaray

http://veritas.sao.arizona.edu

HAWC Gamma-Ray Observatory www.hawc-observatory.org

South Physics Observatorywww.physics.utah.edu/observatory

StarBase Observatorywww.physics.utah.edu/starbase

Telescope Array www.telescopearray.org

W.L. Eccles Observatory www.physics.utah.edu/weo

W.M. Keck Observatorywww.telescopearray.org/tara/index.html

Cosmic Ray ResearchThe history of cosmic ray research is a story of scientific adventure. For over a century, cosmic ray researchers

have climbed mountains, ridden hot air balloons, and traveled to the far corners of the Earth in order to understand these fast-moving particles from space. They have solved some scientific mysteries and revealed many more. With each

passing decade, scientists are discovering higher-energy, increasingly rare, cosmic rays.

TARA ArrayThe Telescope Array Radar (TARA) project is one way in which Telescope Array Scientists are looking towards the future of cosmic ray research. The goal of TARA is to create the world’s first radar observatory for ultra-high energy cosmic rays. Like radar systems used in tracking airplanes or cars on the highway, TARA works by detecting the de-flection of radio waves by the cosmic ray-induced atmo-spheric ionization. TARA scientists will first try to identify the radar echoes of cosmic ray ionization trails. Then, they will use these echoes to test models of radar scattering and to learn to extract the astrophysically interesting characteristics of cosmic rays.

Telescope Array ProjectThe University of Utah is the home institution for the Northern Hemisphere’s larges cosmic ray observatory. Dubbed Telescope Array, the observatory aims to study the most energetic subatomic particles from space. Tele-scope Array was constructed and is maintained by over 100 physicists from Japan, the United States, Korea and Russia. Data taking began in 2007.

from different view points. This leads to recon-struction of the primary particle with great preci-sion and discrimination against cosmic rays.

The gamma ray sky brings us information about the most violent phenomenon in the universe, from super-novae and their possible role in cosmic ray acceleration to the accretion of ma-terial onto super massive black holes in distant galaxies. It is also a window through which the most intriguing questions of astrophysics can be addressed, such as the nature of dark matter and dark energy in the universe.

HAWC

The University of Utah is a partner of the High Altitude Water Cherenkov Observatory (HAWC) Collaboration. HAWC uses an array of large water tanks to detect charged particles created by gam-ma-rays and cosmic rays. These particles exist only at high altitudes, so the HAWC observatory is being constructed at 14,000+ ft above sea level in central Mexico. When particles from the shower pass through the water, they emit Cherenkov light because they travel faster than the speed of light in water. HAWC will be able to observe source of gamma-rays and cosmic rays both day and night, and during inclement weather, thereby expanding upon the capabilities of the optical detection technique employed by VERITAS.

The highest energy cosmic rays pack as much energy as a golf ball driven down a fairway, and they strike Earth at a rate of one per square kilometer per century. Telescope Array currently covers 730 square kilometers of Utah’s West Desert in or-der to capture these rare particles. The cosmic rays are observed using three nitrogen fluorescence telescopes and a separate ground array consisting of over 500 scintillation detectors.

TALEWhile Telescope Array studies cosmic ray particles with energies above 1018 electron-volts (1 EeV), there remain unanswered ques-tions about the cosmic ray energy spectrum and composition at lower energies. Enter the Telescope Array Low-Energy extension (TALE). TALE uses both fluorescence and surface array detectors - similar to Telescope Array - but with varied telescope pointing directions and surface array spacing so as to optimize the detec-tion of particles with energies below 1 EeV. Together, TA and TALE aim to provide seamless coverage over four orders of magnitude in the cosmic ray energy spectrum.

VERITAS Gamma Ray Observatory

VERITAS (Very Energetic Radia-tion Imaging Telescope Array Sys-tem) is a ground-based gamma ray observatory with an array of four 12m Imaging Atmospheric Cherenkov Telescope (IACT) located at the Mt. Hopkins base camp site in southern Arizona. The array allows images of the same shower to be recorded

TARA Array