Dept. of Physics, Director, Enrico Fermi Institute, and the College
My research spans a number of topics in the categories of experimental astroparticle physics and high-energy astrophysics. This includes several investigations into the nature and origin of very high energy (VHE) cosmic radiation, including gamma rays and cosmic rays above 1 GeV. I am also interested in topics at the interface of cosmology and astroparticle physics, including studies of the propagation of VHE gamma rays through extragalactic photon fields. I currently am working on the following projects:
VERITAS - the Very Energetic Radiation Imaging Telescope Array System. This experiment comprises 4 12-meter imaging atmospheric Cerenkov telescopes designed to detect and measure gamma rays over an energy range of ~50 GeV to 50 TeV. VERITAS is the most sensitive instrument of its kind in the northern hemisphere for the investigation of gamma ray sources such as galactic supernova remnants and AGN.
CTA – the Cerenkov Telescope Array. CTA is a world-wide collaboration to build the next generation of ground-based gamma-ray observatory. CTA builds on the success of VERITAS, HESS, and MAGIC, and aims to achieve a sensitivity which is 10 times better than the best of current instruments. CTA is currently in a pre-production phase, with construction expected to begin within a few years at sites in the northern and southern hemispheres.
HELIX - The High-Energy Light Isotope Experiment. The HELIX experiment is a high-altitude balloon-borne magnet spectrometer payload designed to measure the flux of high-energy cosmic-ray isotopes to energies never before explored. HELIX uses a suite of modern particle physics detectors track particles through the field of its 1T superconducting magnet, achieving excellent mass resolution for light (Z<10) isotopes to energies up to 10 GeV/n. The instrument is currently scheduled to fly in Antarctica at the end of 2019.
- Intergalactic Magnetic Fields and Gamma-Ray Observations of Extreme TeV Blazars, Arlen, et al., ApJ 796 (2014).
- Discovery of TeV Gamma-Ray Emission toward Supernova Remnant SNR G78.2+2.1, The VERITAS Collaboration, ApJ 770 (2013).
- Introducing the CTA concept, The CTA Collaboration, Aph 43 (2013).
- Cosmic-ray Proton and Helium Spectra from the First CREAM Flight, The CREAM Collaboration, ApJ 728 (2011).
- Discovery of TeV Gamma Ray Emission from Tycho's Supernova Remnant, The VERITAS Collaboration, ApJL 730 (2011).
- A connection between star formation activity and cosmic rays in the starburst galaxy M82, the VERITAS Collaboration, Nature 462, 770 (2009).