Sarah Shandera
Penn State University

Abstract:

Gravitational wave detections of merging ultracompact objects provide a completely new way to constrain non-minimal dark matter models. If the dark matter consists of a rich spectrum of particles, it will generically contain channels for dissipative energy loss that can lead to the formation of compact objects. We have recently calculated a crucial set of processes for “atomic dark matter” that enable accurate calculations of the spectrum of black holes produced in this scenario. I will show how these results inform gravitational wave searches, as well as the first generation of accurate simulations of structure formation with dissipative dark matter. Current data, especially from searches for sub-solar mass objects, already provide new constraints on the particle physics properties of dark matter. A detection of a dark matter black hole in an upcoming search would be revolutionary, directly bounding the mass of the heaviest fermion in the atomic dark matter scenario and constraining the size of the dark molecular energy gap.

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 2:30 PM in STI 501 and/or on Zoom. Contact Aaron Vincent if you would like to attend through zoom.

Melissa Diamond
Queen’s University

Abstract:

Compact transients such as supernova and binary neutron star mergers can produce enormous fluxes of exotic particles.  One way to look for them is through fireballs, a dense expanding photon electron plasma formed when exotic particles escaping a compact source quickly decay to the standard model.  Fireballs produce a unique signal, allowing us to observe new parts of dark photon and axion parameter space.  Fireballs from the neutron star merger GW170817can produce new constraints on axions with masses between 1 MeV and 1 GeV, while a fireball from SN1987a opens up previously ruled out parameter space.

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 2:30 PM in STI 501 and/or on Zoom. Contact Aaron Vincent if you would like to attend through zoom.

Victoria Kaspi
McGill University

Abstract:

In 2007, astronomers discovered a new mysterious cosmic phenomenon:  Fast Radio Bursts. These events consist of short, intense blasts of radio waves arriving from far outside our Milky Way galaxy. Their origin is unknown, however Fast Radio Bursts appear ubiquitous in our Universe, with roughly 1000 arriving every day over the full sky. I will describe the Fast Radio Burst mystery and what is presently known about it, and present a revolutionary new radio telescope recently built in Canada that is enabling astronomers to make major progress in our understanding of the FRB puzzle.

George & Maureen Ewan Lecture Series

This talk is part of the George & Maureen Ewan Lecture Series. Dr. Ewan focused on nuclear physics and sub-atomic research, particularly the solar neutrino problem as a co-founder of the Nobel Prize-winning Sudbury Neutrino Observatory (SNO) experiment. With his work recognized at the highest level, Dr. Ewan pushed ahead with a goal of influencing the next generation of scientists here at Queen’s, remarking that “it is vital that we scientists make our work accessible to the general public.” His wife, Maureen, agreed, saying “his work is so remote from what most people would find comprehensible.” Effective communication skills are vital to successful research. As he put it, scientists have so much of value to share with the world. “As a rule, scientists don’t inform the educated public, there are people who work on exciting experiments who could give very good talks. My dream is to have them come to Queen’s to give lectures on the state of their experiments and especially about their results, and to do it in a way that people without PhDs can understand.”

This is why Dr. Ewan and his wife decided to donate $100,000 to Queen’s to create the George & Maureen Ewan Lecture Series, which will support seminar and lecture programs designed to increase scientific discourse and culture within the Particle Astrophysics community at Queen’s University.

Dr. Ewan’s gift gives the department access to $10,000 a year until the fund is depleted. A $10,000 annual budget will make it possible for the department to look farther afield for guest lecturers and host them for a longer stay. “The idea is to have the guest lecturers stay for a while and spend some quality time with the students, interacting with them and working with them in the labs,” says Dr. Tony Noble, former SNOLAB director and the current Scientific Director of the Arthur B. McDonald Canadian Astroparticle Physics Research Institute.

The McDonald Institute and Queen’s University are very excited about the opportunities offered by The Ewans’ generous endowment, and look forward to organizing public lectures that will benefit researchers in the Physics department, and the wider Queen’s and Kingston communities!

Abigail Crites
Cornell University

Abstract

I will discuss line intensity mapping (LIM) and its applications for understanding cosmology and star-formation across cosmic time. I will focus on TIME, a mm-wavelength instrument designed to use LIM to probe the [CII] line at redshifts ~5-9 and the CO lines at redshifts ~0.5-2. The instrument is a grating spectrometer with transition edge sensors that is used on the Arizona Radio Observatory 12m. I will also briefly touch on other instruments and facilities that will be used for LIM and the future of cosmology using this technique.

Eden Hennessey
Wilfred Laurier University

Abstract

What do we know about the physics community in Canada in terms of people's identities and experiences? In Canada, there has never been an assessment of physics students, scholars, and professionals. In this talk, Dr. Hennessey will present findings from the first nation-wide survey of equity, diversity, and inclusion (EDI) in the physics community in Canada. Intersectional analyses revealed several central findings related to identity and harassment experiences across all levels and areas of physics, underscoring notable underrepresentation and harm reported by gender diverse and racialized physicists. Based on these findings, Dr. Hennessey will discuss opportunities for action and propose recommendations to contribute to a more diverse and inclusive physics community in Canada. 

Olga (Liliana) Caballero Suarez
University of Guelph

Abstract

Elusive neutrinos are a window to the interior of compact objects. Their weakly interacting character allows them to decouple from highly dense stellar matter, much deeper than photons, and travel longer distances with no deflection. Thus, MeV neutrinos have the potential of unveiling the behavior of phenomena such as neutron star mergers, core-collapse Supernovae, and the synthesis of elements. As standalone detection or in the context of multi-messengers signals, neutrinos offer opportunities to understand our Universe in unprecedented ways. Interpreting neutrino observations relies on models of neutrino emission and their interaction with nuclear matter. In this colloquium,  I shall discuss neutrino emission from astrophysical environments like collapsars and neutron-star mergers, their influence on the synthesis of heavy elements, show results on relic neutrinos, and the possibility of testing models of the nuclear force.

Ron Vincent
RMC

Abstract

On a geologic timescale the climate of Earth is constantly changing, fluctuating between eras of extreme warmth and frigid cold. The geologic record indicates that sudden changes in climate coincide with mass extinctions over relatively short periods of time.  The mechanisms for climate change are varied, complex and difficult to model. In the Anthropocene Epoch there is an additional factor that must betaken into consideration: human activity.  This talk will cover the basic physics of climate change and compare the current trend of rising temperatures to the geologic record.  There will be an emphasis on Polar Amplification and the near-term consequences.