This award is funded under the American Recovery and Reinvestment Act of 2009 (Public Law 111-5). It will provide support for the research activities of this group with the Pierre Auger Observatory (PAO) in pursuit of the origins of the highest energy cosmic rays. The PAO is the world's largest experiment to measure the energy and arrival direction of energy cosmic rays with energies above 10**20 eV. The origin of cosmic rays remains a profound and compelling mystery in particle astrophysics. PAO is a hybrid detector consisting of two detector systems: (1) an array of 1,600 water-Cherenkov Surface Detector stations spread over 3,000 square kilometers for detecting air shower particles on the ground; and (2) a set of four Fluorescence Detector telescopes which provide calorimetric measurements of the development of cosmic ray showers as they propagate through the atmosphere. Located near Malargue, Argentina, PAO is now complete and collecting data.
During the past two years, the first major scientific results from Auger have been published. These results include an energy spectrum and the detection of anisotropy in the arrival directions of the highest energy cosmic rays which appear correlated with the distribution of large scale matter in the relatively nearby galactic neighborhood. The Case Western group is pushing a new analysis effort to consider what might be possible in the context of "cosmic ray astronomy" as the number of events collected from Auger increases. They also continue to lead the effort on GPS event timing and calibration, working closely with their colleagues at the Colorado School of Mines to develop and deploy a new laser calibration facility located at the center of the Auger array.
This work has a broader impact on several areas outside of particle astrophysics. The PI is active in a variety of education and outreach programs, including a program for physical science instruction for high school teachers. Methods developed by the group for precise few-nanosecond timing using GPS receivers and non-imaging optical concentrators also have a broader impact in other technical fields.
