Seyda Ipek
Carleton University

Abstract:

One of the most famous dark matter candidates is the weakly interacting massive particles, WIMPs. Our theories for WIMPs rely on a standard cosmological history, in which WIMP particles annihilate into (massless) SM fermions. At some point these annihilations freeze out and the WIMP number density becomes a constant. However, the parameter space for this simple is under increasing scrutiny from various direct detection experiments. I will give an example of a non-standard cosmological history in which the WIMP scenario works as well without being excluded by direct detection experiments.

McDonald Institute seminars bring together experimental and theoretical astroparticle physicists and astronomers. They are held approximately fortnightly, September to November and January to March, and on an ad hoc basis outside of term. They currently take place on Thursdays at 3:30 PM in STI 501 and/or on Zoom. Contact Aaron Vincent if you would like to attend.

Samantha Lawler
University of Regina

Abstract

Several companies are planning to launch megaconstellations of thousands of communication satellites (satcons), which would increase the number of active satellites in Low Earth Orbit at least twenty-fold in the next few years. SpaceX's Starlink satcon is currently largest (almost 2,000 satellites) and is adding 60 new satellites every couple of weeks.  While these satcons do allow internet access in many underserved rural and remote locations, the costs are prohibitively high for all but the most well-off customers. These thousands of satellites each reflect sunlight, causing serious problems for research astronomy, and making anthropogenic light pollution a fully global phenomenon that cannot be escaped anywhere on Earth.  Our recent simulations show that because of geometry and the chosen satellite orbits, latitudes near 50 degrees N and S will see the worst light pollution from these satcons, with hundreds of naked-eye visible satellites all night long in the summer. These satellites also contribute to significant atmospheric pollution, both on launch and re-entry, contribute to diffuse sky emission, and drastically increase the very real threat of Kessler Syndrome. I will talk about how these satellites will affect stargazers and astronomers worldwide, and what you can do to help mitigation efforts.

Yue Zhang
University of Carleton

Abstract

The recent discoveries of the Higgs boson and gravitational waves marked the triumph of two cornerstones of modern physics, the standard model of elementary particles and Einstein’s theory of gravity. However, overwhelming evidence from cosmology suggests that the standard model is inadequate for understanding our universe. There is stuff gravitating that we cannot see with light. In particular, the identity of dark matter which comprises eighty-percent of the matter in the universe, remains unknown. In this talk, I will discuss potential intimate connections between dark matter and neutrinos from early universe to the present. I will tell a new story of an old dark matter candidate, the sterile neutrino, and highlight how new theories for neutrino self-interaction are driving us to novel frontiers of dark matter searches.

Nobel Laureate and Professor Emeritus Art McDonald
Queen's University

Nobel Research Public Lecture

Katie Mack
NCSU

Abstract:

TBA