McGill Physics: Research

Particle Astrophysics

Particle Astrophysics (also called Astroparticle Physics) is a relatively new area of research where ideas and data from elementary particle physics are applied to topics in astrophysics and cosmology, or vice versa.

On the theoretical side this has been going on for many years where, for example, theories of nuclear and particle physics can be used in calculating details of stellar evolution or the very early history of the Universe itself.

VERITAS array»

The four 12-m telescopes of the VERITAS array, now operating at the Mt. Hopkins site (Arizona) to detect high-energy gamma rays.

Experimentally, one can use techniques and instruments developed for use at accelerator laboratories to make astronomical observations using gamma rays, neutrinos and cosmic rays, thus extending our view of the Universe beyond that accessible using more the more traditional messengers of astronomy, such as optical photons and radio waves. For example, in searches for exotic particles such as those which may make up the mysterious dark matter, astrophysical observations are complementary to lab-based searches and can explore a greater range of masses.

The High-Energy Astrophysics group is part of the VERITAS collaboration which operates an array of four 12-m imaging atmospheric Cherenkov telescopes in southern Arizona. With this instrument we carry out a program of very-high-energy (VHE) gamma-ray astronomy, observing photons with energy in the range from 50 GeV to 50 TeV. Sources of such photons are among the most violent and exotic in the Universe and include supernova remnants and pulsar wind nebula in our galaxy, as well as blazar-class active galactic nuclei (AGNs) at cosmological distances.

VHE source catalog »

The current (September 2012) map of known very high-energy (VHE, E>100 GeV) sources, from tevcat.uchicago.edu , in galactic coordinates. The different colours represent different types of source, including active galactic nuclei (red), supernova remnants (green), and unidentified sources (grey). The total VHE source count has increased by an order of magnitude over the last decade, with VERITAS discovering nearly 20 of those since 2007.

Discovery and characterization of new sources are part of our research program but it also includes topics in particle-astrophysics. Examples include tests of Lorentz invariance using AGN flares and searches for gamma rays coming from annihilation of dark matter particles in high density environments like dwarf Galaxies. The group also develops instrumentation for the VERITAS detector including calibration and characterization devices.