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Past Colloquia

Milky Way Stellar Stream Heating

AB107, 50 St. George Street

Raymond Carlberg, University of Toronto

January 25, 2023
3:00pm - 4:00pm

A key prediction of LCDM is that galactic halos are filled with sub-halos orbiting within them, whereas warm dark matter models would have few. Studies of individual Milky Way star streams find evidence of a few sub-halos, but the sub-halo population properties are unclear. Current…

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The Landscape of Relativistic Stellar Explosions

Cody Hall

Prof. Anna Ho, Cornell

January 18, 2023
3:00pm - 4:00pm

For the last half-century, relativistic outflows accompanying the final collapse of massive stars have predominantly been detected via high-energy emission, as long-duration gamma-ray bursts (GRBs). Yet, it has long been hypothesized that GRBs are the tip of the iceberg of relativistic stellar explosions, because the…

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Direct Detection Searches for Low-Mass Dark Matter Particles

Cody Hall

Miriam Diamond

January 11, 2023
3:00pm - 4:00pm

The quest to unmask the fundamental nature of dark matter has inspired a vast worldwide program of complementary experiments, including direct-detection, indirect-detection, and collider searches.Direct-detection searches over the past few decades, using technologies such as large liquid noble chambers, have been largely focused on Weakly Interacting Massive Particles in…

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Discovering the cold extrasolar planets with gravitational microlensing

Online Zoom

Prof. Shude Mao

December 07, 2022
11:00am - 12:00pm

Microlensing has become a powerful method to detect cold extrasolar planets beyond the snowline and free-floating planets. In this talk, I will first introduce the basic concepts of gravitational microlensing, review some of the recent discoveries with ongoing surveys, and then finish with a discussion…

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The Far Ultraviolet diffuse background

AB 107, Codyhall

Shrinivas Kulkarni, Caltech

November 23, 2022
3:00pm - 4:00pm

Historically, the search for the inter-galactic medium(IGM) motivated the search for  the Far Ultraviolet (FUV) backgroundwhich in turn led to a number of experiments and missions.  Decadeslater the focus shifted to FUV as the primary heating and ionizingagent of the atomic phases (warm and cold…

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A Golden Age of Asteroseismology with Kepler and TESS

Zoom

Tim Bedding

November 16, 2022
3:00pm - 4:00pm

Asteroseismology uses the natural oscillation modes of stars to study their interiors. The wonderfully precise measurements by NASA’s Kepler and TESS missions are ideal data sources for the technique. These space telescopes have been monitoring the brightness of hundreds of thousands of stars, with the…

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Galaxy evolution in and around the circumgalactic bubble: New discoveries with CHaS and beyond

AB 107, Codyhall

David Schiminovich

November 02, 2022
3:00pm - 4:00pm

Despite tremendous progress in the 65 years since a possible interstellar “galactic corona” was first postulated, the study of warm-hot galactic atmospheres—now commonly referred to as the circumgalactic medium (CGM)—remains one of the last great baryonic frontiers in our developing census of the Universe.  In…

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Observing the hierarchical formation of our Milky Way

AB 107, Codyhall

Alan McConnachie, NRC Herzberg

October 26, 2022
3:00pm - 4:00pm

2024 will be the 30th anniversary of the discovery of the Sagittarius dwarf galaxy, the prototype and nonpareil of a galaxy in the process of being consumed by our Milky Way. It remains the most striking evidence for the ongoing hierarchical formation of galaxies in our…

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Black holes and revelations: unseen companions in stellar binaries

AB 107, Codyhall

Kareem El-Badry

October 19, 2022
3:00pm - 4:00pm

The Milky Way contains of order 10^8 stellar-mass black holes (BHs). Yet, fewer than 100 BH candidates are known, and only about 20 are dynamically confirmed. Our view of the BH population has been shaped almost entirely by observations of X-ray binaries and gravitational wave…

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The Irregular Moon Systems of the Giant Planets

AB 107, Codyhall, 50 St. George Street Toronto

Brett Gladman

September 28, 2022
3:00pm - 4:00pm

Each of our giant planets has a regular and an irregular systemof moons.  Regular moons lie very close to the planet’s equatorialplane on nearly-circular direct orbits that share the planetaryrotational sense, and likely formed in the disk.  Irregular moons,in contrast, orbit at nearly all orbital…

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