Canadian Particle Astrophysics Research Centre

Science Talks


Upcoming
Ue-Li Pen (Toronto) | Apr 6 2018
Past
Neal Dalal (Perimeter) | Mar 20 2018
Scott Watson (Syracuse) | Mar 13 2018
Barry Barish (Caltech) | Mar 6 2018
Markus Rummel (McMaster) | Feb 13 2018
Glenn Starkman (CWRU) | Feb 9 2018
Sherry Suyu (MPA) | Nov 8 2017
Niayesh Afshordi (Perimeter) | Oct 31 2017
Henk Hoestra (Leiden) | Aug 29 2017

Science Talks

Thanks to CPARC, a number of great researchers are being invited to Queen's University in Kingston, ON and will be giving scientific talks during their stay. Departmental Colloquia are typically accessible at an undergraduate physics major level, whereas CPARC Seminars are accessible at a physics graduate student level. All talks are open to the public and there is no admission fee. Please contact our Education & Outreach Officer if you have any questions!

Upcoming Talks

Dpmt Colloquium | Prof. Ue-Li Pen (U of Toronto) | Apr 6 2018

Location: Stirling A, Queen's University, Kingston, ON
Time: 2:30pm-3:30pm
Title: Natural Cosmic Telescopes
Abstract:
Interstellar radio plasma lenses can act as natural telescopes with unprecedented resolution. We present a new tool set for direct measurement of small scale structure in pulsars, interstellar and other astrophysical plasmas. VLBI allows a direct map of the lens geometry and properties, yielding a surprising picture of interstellar magnetic domain boundaries. I present recent results on the crab pulsar, PSR B0834+06, black widow PSR B1957+20 and FRB1105023, and prospects for gravitational wave localization, Fast Radio Bursts and beyond.

Past Talks

CPARC Seminar | Prof. Neal Dalal (Perimeter Institute) | Mar 20 2018

Location: Stirling 501, Queen's University, Kingston, ON
Time: 2:30pm-3:30pm
Title: Dark Matter with ALMA
Abstract:
The Missing Satellites Problem has remained one of the key challenges to the (otherwise) wildly successful standard cosmological model, called ΛCDM. This model predicts that galaxies like our own Milky Way should host many thousands of small satellites, an abundance vastly exceeding the number of detected satellite galaxies. This discrepancy either represents our first evidence for non-gravitational physics in the dark sector, or alternatively, it means that most of this low-mass substructure must be dark. Distinguishing these scenarios requires a method to detect completely dark objects, and I will describe how gravitational lensing may be used to measure the abundance of dark matter substructure around typical galaxies. In particular I will discuss how the new ALMA observatory is revolutionizing lensing studies of dark matter, and I will present first results from our ongoing project to use ALMA to probe dark matter physics.

CPARC Seminar | Prof. Scott Watson (Syracuse University) | Mar 13 2018

Location: Stirling 501, Queen's University, Kingston, ON
Time: 12:30pm-1:30pm
Title: Concentrated Dark Matter
Abstract:
I will discuss a new mechanism for the primordial creation of dark matter, “co-decay”, where hidden sector particles comprising the dark matter have little or no interaction with the Standard Model. So how does one detect it? The hidden sector leads to a matter-dominated phase before Big Bang Nucleosynthesis, which results in enhanced growth of dark matter on small scales and the production of primordial black holes. If the enhanced sub-structure survives until today it implies interesting implications for indirect detection experiments. Whereas a more provocative result is that the mass of the most populated black holes resulting from this epoch is within the mass range recently detected by LIGO. I will also discuss how the hypothesis that part of the dark matter is primordial black holes can be tested.

Dmpt Colloquium | Prof. Barry Barish (California Institute of Technology) | Mar 6 2018

Location: Stirling D, Queen's University, Kingston, ON
Time: 10:30am-11:30am
Title: Gravitational Waves: Detectors, Detections and the Future
Abstract:
This observation of gravitational waves came after more than fifty years of experimental efforts to develop sensitive enough detectors to finally observe the tiny distortions in spacetime from gravitational waves. The experimental principles, techniques and performance of LIGO will be presented, as well as a review of the observations of compact binary mergers to date. The plans and prospects for gravitational wave science in the future will also be explored.

CPARC Seminar | Dr. Markus Rummel (McMaster University) | Feb 13 2018

Location: Stirling 414, Queen's University, Kingston, ON
Time:2:30pm-3:30pm
Title: Axion-Like-Particles, X-rays and dark matter
Abstract:
Axion-Like Particles (ALPs) are light particles that are among the leading candidates for new physics beyond the standard model. Their coupling to electromagnetism leads to a rich phenomenology, in particular in astrophysical environments. X-ray data on galaxy clusters and active galactic nuclei allows to constrain the properties of ALPs and/or give hints for new physics, including dark matter.

Dpmt Colloquium | Prof. Glenn Starkman (Case Western Reserve University) | Feb 9 2018

Location: Stirling A, Queen's University, Kingston, ON
Time: 2:30pm-3:30pm
Title: An Uncooperative Universe: Large Scale Anomalies in the CMB
Abstract:
The Cosmic Microwave Background Radiation is our most important source of information about the early universe. Many of its features are in good agreement with the predictions of the so-called standard model of cosmology -- the Lambda Cold Dark Matter Inflationary Big Bang Theory. However, the large-angle fluctuations of the microwave background are uncooperative with "the program" -- they continue to exhibit several statistically significant anomalies. On the one hand, if we look at the whole sky the lowest multipoles seem to be correlated both with each other and with the geometry of the solar system. On the other hand, when we look just at the part of the sky that we most trust – the part outside the galactic plane - there is a dramatic lack of large angle correlations. So much so that it challenges basic predictions of the standard model. These anomalies either reflect fundamental new physics of great importance, or our remarkable ability as humans to see patterns where there are none. I will discuss how we might begin to test which of these is the case, even without a model for the anomalies.

CPARC Seminar | Dr. Sherry Suyu (Max Planck Institute for Astronomy) | Nov 8 2017

Location: Stirling 501, Queen's University, Kingston, ON
Time: 12:30pm-1:30pm
Title: Shedding Light on the Dark Cosmos through Gravitational Lensing
Abstract:
Gravitational lensing provides powerful means to study dark energy and dark matter in the Universe. In particular, strong lens systems with measured time delays between the multiple images can be used to determine the "time-delay distance" to the lens, which is primarily sensitive to the Hubble constant. Measuring the Hubble constant is crucial for inferring properties of dark energy, spatial curvature of the Universe and neutrino physics. I will describe the ingredients and newly developed techniques for measuring accurately time-delay distances with a realistic account of systematic uncertainties. A program initiated to measure the Hubble constant to less than 3.5% in precision from gravitational lens time delays is in progress, and I will present the latest results and their implications. Search is underway to find more time-delay lenses in ongoing imaging surveys. An exciting discovery of the first strongly lensed supernova has offered a rare opportunity to perform a true blind test of our modeling techniques. I will show the bright prospects of gravitational lens time delays as an independent and competitive cosmological probe.

CPARC Seminar | Prof. Niayesh Afshordi (Perimeter Institute) | Oct 31 2017

Location: Stirling 501, Queen's University, Kingston, ON
Time: 11:30am-12:30pm
Title: Seeing Dark in the Extremes: from nanostructure, to infinity and beyond

CPARC Seminar | Prof. Henk Hoestra (Leiden Observatory) | Aug 29 2017

Location: Stirling 501, Queen's University, Kingston, ON
Time: 2:00pm-3:00pm
Title: Weak lensing as an accurate probe of cosmology and much more!
Abstract:
Weak lensing by large-scale structure is one of the most promising techniques to learn more about the nature of dark energy by mapping the dark matter distribution in the Universe as a function of distance. Weak lensing has also developed into the main tool to determine cluster masses, critical for their use for cosmology, but can also be used to study the dark matter halos of galaxies. I will review the recent progress in this active area of research and discuss the prospects for future projects, such as Euclid.