Baseline Support of the University of Utah Cosmic Ray Physics Group Including Analysis of Telescope Array, TALE, and TAx4 Data

University Of Utah, Salt Lake City UT

Investigators

Abstract

Cosmic rays are highly energetic sub-atomic particles from space that travel at velocities near the speed of light. The origin of cosmic rays and their acceleration mechanisms are unknown, but they likely originate in extreme astrophysical phenomena both within and beyond our galaxy. The Telescope Array (TA) is the largest cosmic ray observatory in the northern hemisphere. Located outside Delta, Utah, and representing a joint US-Japanese effort, TA was designed to study the nature and origin of the highest energy particles in the Universe. This award to the University of Utah supports the scientific analysis of data from TA and the TAx4 upgrade that is currently under construction. The University of Utah is the host institution for TA and therefore plays a critical role in scientific activities of the observatory. This award will also support the University of Utah group's involvement in the Astrophysics Science Project Integrating Research and Education (ASPIRE) program, which engages area teachers, students, and the public through a web site of interactive educational materials and visits to local schools. The group will also host associated experiments in other fields that benefit from the TA location and infrastructure. The primary objectives of the TA experiment are to measure the energy and spatial distributions, and the chemical composition of the highest energy cosmic rays in order to address the nature and origin of ultra-high energy cosmic rays. Through this award, the group will work to substantially improve the event statistics of the anisotropy data set and clarify the nature of the apparent "hotspot" in the northern sky. They will improve the precision of the spectrum measurement in order to elucidate the nature of the suppression in the cosmic ray energy spectrum at high energies. With increased statistics from hybrid data they will improve and extend measurements of the shower maximum depth to resolve the composition of cosmic rays at the highest energies. This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.