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The Formation, Evolution, and Structure of Galaxies - Associate Prof. J. English Recent research challenges the notion that the structure, and evolution, of spiral galaxies is soley dependent on the rate at which the stars in the galactic disks ignite and die. In particular, studies of the spurs which are observed to extend vertically from the disks into galaxy halos are revolutionizing our understanding of the disk-halo interface. Our collaborative studies of ionized and neutral hydrogen gas, distribution of stars, and cosmic rays in galaxies have contributed to this recent progress. In order to examine the vertical extensions in detail, we also study the behaviour of the relatively nearby neutral hydrogen gas columns in our own Milky Way galaxy. This latter study is part of the Canadian Galactic Plane Survey. A complementary project, using the Hubble Space Telescope, examines extensions which include stars; these would form when galaxies interact with each other. High-energy astrophysics of neutron stars, microquasars and supernova remnants - Associate Prof. S. Safi-Harb As stars evolve, they die as they run out of nuclear energy. Their death yields a catastrophic event: a supernova (SN) explosion which, in some cases, gives birth to a neutron star: a compact star the size of a city. Neutron stars act like a lighthouse, and emit beams of radiation (pulses, thus their name pulsars), seen from radio wavelengths to the highest energy gamma-rays. The explosion forms a blast wave which sweeps space with vast speeds shocking the surrounding medium, enriching it with metals originating from the exploded star, and accelerating particles to very high energies. The remnants of the explosion form the so-called supernova remnant (SNR), which can survive thousands of years after the explosion. The study of neutron stars and supernova remnants thus help us understand the latest stages of stellar evolution, the composition of the interstellar medium, and the origin of high-energy cosmic rays. Evolution Meets Astrophysics: Genetic Algorithms in Submillimetre Astronomy & Planetary Science - Assistant Prof. J. Fiege Dr. Jason Fiege works on a variety of problems that bridge the gap between astrophysics theory and observational astronomy. These problems have a common approach, which uses powerful computational techniques to search very large parameter spaces for families of theoretical solutions that agree with observational data. Much of this work involves building detailed mathematical models of the density and magnetic field structure of regions in our Galaxy that are in the process of forming stars, and comparing these models to data obtained at the James Clerk Maxwell Telescope (see Figure). A second major line of research involves modeling three of Jupiter's moons, namely Europa, Callisto and Ganymede, which are particularly interesting because they harbour oceans of liquid saltwater beneath a crust of water ice. Europa is also interesting from an astrobiological perspective because its ice layer may be relatively thin, and its global ocean could provide a habitable environment for extraterrestrial microorganisms. Theoretical Astrophysics: Propagation and Acceleration of Cosmic Rays - Assistant Prof. A. Shalchi A fundamental problem in astrophysics is the interaction between space plasmas and energetic particles. Space plasmas can be found in any astrophysical scenario. This could be the plasma of the solar wind or the interstellar medium. Examples of energetic particles are the so-called Solar Energetic Particles (SEPs) and Cosmic Rays. These particles experience strong scattering while they propagate through interplanetary or interstellar space. Describing those scattering effects theoretically is important to understand the motion of Cosmic Rays through the Universe and the mechanism of diffusive shock acceleration. The latter mechanism is important for understanding the origin of cosmic radiation. Dr. Andreas Shalchi employs computer simulations as well as analytical theory to explore these scattering mechanisms. The theoretical results are applied to different physical scenarios such as Cosmic Ray propagation and acceleration of particles at interplanetary shocks and supernova remnants.