Study of the Highest Energy Cosmic Rays with the Pierre Auger Observatory

Colorado School Of Mines, Golden CO

Investigators

Abstract

Cosmic rays are highly energetic sub-atomic particles from space that travel at velocities near the speed of light. The origin and acceleration mechanism for ultra-high energy cosmic rays, which likely come from extreme astrophysical phenomena outside our galaxy, are currently unknown. The Pierre Auger Observatory is the largest cosmic ray detector ever operated, with an instrumented area of more than 3000 square kilometers. Built in Malargue, Argentina by an international collaboration, the Pierre Auger Observatory was designed to study the origin and interactions of the highest energy particles in the Universe. This award supports the astroparticle group at the Colorado School of Mines in their work on Auger to address systematic uncertainties in the measured energy and composition of cosmic rays. They will utilize a recently completed upgrade to the laser calibration systems at Auger. They are also installing and will operate Auger detector tanks on the site of another cosmic ray observatory, the Telescope Array in Utah, to cross-calibrate the detectors from both observatories. The work of the Colorado School of Mines group also has broader applications to atmospheric sciences. They will use the laser calibration system to validate and then share atmospheric aerosol measurements. They will use the Auger optical detectors to study light emitted in the ionosphere about 90 km above certain thunderstorms. They plan to host a conference on interdisciplinary science with astroparticle detectors. The Colorado School of Mines group will focus on improved air shower reconstruction methods and detailed measurements of systematic effects to address the unresolved discrepancies in cosmic ray data. The Raman LIDAR on the Auger Central Laser Facility will be used as independent atmospheric calibration. The Auger water Cherenkov Surface Detector tanks installed at the Telescope Array site will be used for a detailed cross-calibration between Auger, which views the southern sky, and Telescope Array, which views the northern sky. Planned analysis of the Auger data includes developing a new method to reconstruct air showers with the Surface Detectors, and developing a method for anisotropy scans that include energy and angular uncertainties.