Particle Astrophysics with HAWC and Milagro

Michigan State University, East Lansing MI

Investigators

Abstract

This award is funded under the American Recovery and Reinvestment Act of 2009 (Public Law 111-5). It will provide funds for this group to work on Milagro, a TeV cosmic gamma ray experiment, and HAWC, a successor to Milagro. Very high energy gamma ray astronomy probes some of the most extreme environments in the known universe. Known sources of TeV gamma rays include compact objects (black holes or neutron stars) with intense gravitational and/or magnetic fields: examples include supernova remnants within our galaxy and active galactic nuclei outside of our galaxy. Possible new TeV sources include gamma ray bursts, micro-quasars, and diffuse emission from cosmic rays interacting with matter in our own galaxy. Milagro, the first TeV detector continuously monitoring the entire overhead sky at energies above a few hundred GeV, operated 2000-2008. Final calibrations and improved corrections for time dependences of the apparatus will enable a reliable energy scale and the determination of the energy spectrum of the gamma ray sources that Milagro discovered. Another product will be comprehensive sky maps, whose power will be used to search for TeV emission of all Fermi sources. HAWC will also be able to sensitively observe many of the Fermi sources. The broader impact of the program includes presentations of Milagro to high schools and junior colleges and a 'Frontiers in Science' workshop for secondary school teachers. Milagro has been active in exposing students and the general public to the excitement of the field and was one of the first Particle Astrophysics experiments to join Quarknet - a program to bring active physics experiments into the classroom by involving classroom teachers in research.