Events List for the Academic Year

Event Time: Monday, August 30, 2021 | 3:00 pm - 4:00 pm
Event Location:
Connect via zoom
Add to Calendar 2021-08-30T15:00:00 2021-08-30T16:00:00 Even more student presentations Event Information: Caleb Lammers: "Candidate High-Redshift Protoclusters and Gravitationally Lensed Galaxies in the Planck High-z Catalogue" Justin Lawrence: "Dark matter search limits and sensitivities with extragalactic dark matter components" Erik Gillis: "An RRAT Census with CHIME/PULSAR" Event Location: Connect via zoom
Event Time: Thursday, August 26, 2021 | 4:00 pm - 5:00 pm
Event Location:
Connect via zoom
Add to Calendar 2021-08-26T16:00:00 2021-08-26T17:00:00 Fun Fysics Films Event Information: It's the end of the summer, so let's have a completely informal meeting this week! For the last colloquium slot before term starts, we'll have a discussion around some physics-related content from youtube and other video sources.  Some of our regular attendees have shared suggestions for amusing and/or informative bits of physics video, which we'll show.  If your favourite science clip isn't included, perhaps there will be time for additional examples at the end. Event Location: Connect via zoom
Event Time: Monday, August 23, 2021 | 3:00 pm - 4:00 pm
Event Location:
Connect via zoom
Add to Calendar 2021-08-23T15:00:00 2021-08-23T16:00:00 More student presentations Event Information: Keshav Gopinath: "MUSE Spectrograph and the analysis of a candidate group with a lensed quiescent galaxy" Timothy Yu: "The Study of Molecular Gas Content of Massive Quiescent Galaxies at z~2" Hao Tse (Howard) Huang: "Multi-tracer investigation of molecular gas in a massive radio galaxy" Event Location: Connect via zoom
Event Time: Thursday, August 19, 2021 | 4:00 pm - 5:00 pm
Event Location:
Connect via zoom
Add to Calendar 2021-08-19T16:00:00 2021-08-19T17:00:00 Echoes Made Simple Event Information: Echoes are common in many areas of physics, including NMR, plasma physics, nonlinear optics, cavity quantum electrodynamics, cold atoms physics, and dynamics of proton storage rings.  Recently, we theoretically found (probably) the simplest classical system featuring the echo phenomenon — a collection of randomly oriented free rotors with dispersed rotational velocities. The mechanism of this echo is based on the kick-induced filamentation of the rotational phase space, and I will present a simple toy model explaining this phenomenon at the high school level.  This prediction was confirmed in a dozen laser experiments on molecules and resulted in an efficient tool for studies on collisional relaxation in dense molecular gases. The described mechanism of the rotational echo formation is rather general. It has implications in other areas of physics ranging from high harmonics generation in free-electron lasers to the spectroscopy of gravitational quantum states of ultra-cold neutrons, atoms, and anti-atoms bouncing in the Earth’s gravitational field. Event Location: Connect via zoom
Event Time: Thursday, August 12, 2021 | 4:00 pm - 5:00 pm
Event Location:
Connect via zoom
Add to Calendar 2021-08-12T16:00:00 2021-08-12T17:00:00 Explaining Science Visually Using Graphics and YouTube Event Information: In this talk Dr Walliman shows how he uses graphics, illustration and animation to explain science on his popular YouTube channel Domain of Science. He explains his approach to science communication and his focus on context setting. For a case study he looks at the field of physics at three levels: the whole field, expanding in on quantum physics and finally looking at the fundamental particles of the standard model of particle physics. Event Location: Connect via zoom
Event Time: Monday, August 9, 2021 | 3:00 pm - 4:00 pm
Event Location:
Connect via zoom
Add to Calendar 2021-08-09T15:00:00 2021-08-09T16:00:00 Enabling Infrared Surveys of Galaxies with Innovative Imaging Spectrographs Event Information: Optical integral field (imaging) spectroscopic surveys of large numbers of galaxies are now becoming the norm. These surveys allow detailed studies of individual galaxies, which include their stellar/gas kinematics and stellar populations. With a sufficiently large sample, these types of observations are the best tools for understanding the formation and evolution of galaxies. However, similar surveys in the infrared remain challenging. There are two significant gaps that need to addressed: the rest-frame infrared has been untapped for nearby systems due to the lack of wide integral field infrared spectrographs (IFSes), and rest-frame optical observations of the distant universe have been limited to small samples from the lack of high angular resolution, highly multiplexed IFSes.  I will discuss two instruments that will directly address these gaps: one recently commissioned, the wide integral field infrared spectrograph (WIFIS), and another currently under construction, the Gemini Infrared Multi-object Spectrograph (GIRMOS). WIFIS is currently carrying out an infrared survey of nearby galaxies that studies their stellar populations (particularly their initial mass functions), star-formation, and kinematics, complementing existing optical surveys such as CALIFA and MaNGA. On the other hand, GIRMOS will be a multi-object IFS that takes advantage of the latest developments in adaptive optics and infrared spectroscopy. It will carry out large surveys of the distant universe by simultaneously observing multiple high-redshift galaxies, which will finally complement, in a similar scale, the integral field studies being done in the local universe. Event Location: Connect via zoom
Event Time: Thursday, August 5, 2021 | 4:00 pm - 5:00 pm
Event Location:
Connect via zoom
Add to Calendar 2021-08-05T16:00:00 2021-08-05T17:00:00 Statistics of Ambiguous Rotations Event Information: If an object is symmetric, then there are numerous equivalent ways to describe its orientation in space.  For example, the lattice of a crystal with cubic symmetry can be mapped onto itself by 24 rotations.   The statistics of the orientations of such objects, even exercises as simple as finding the average orientation, are made complicated by these symmetries. Using examples from seismology and materials science, Richard Arnold will discuss the range of problems that arise when working with such ambiguous orientations.  He will present new families of probability distributions and statistical tests associated with these objects. Bio: https://people.wgtn.ac.nz/Richard.Arnold Event Location: Connect via zoom
Event Time: Thursday, July 29, 2021 | 4:00 pm - 5:00 pm
Event Location:
Connect via zoom
Add to Calendar 2021-07-29T16:00:00 2021-07-29T17:00:00 Heatwave: A Synoptic Breakdown Of The Extraordinary Heatwave On The Pacific Coast Of The US And Canada in June 2021 Event Information: In late June 2021, the Pacific Northwest experienced extraordinarily high temperatures. British Columbia alone recorded over 60 record high temperatures, with the town of Lytton setting an all-time high temperature in Canada for three consecutive days, peaking at 49.6 C (121.3 F). During this talk, we will explore the meteorological conditions that led to these extreme temperatures—analyzing the upper air dynamics, mid-level thermal anomalies, and terrain effects during the event. We will also delve into the societal and environmental impacts regionally. Event Location: Connect via zoom
Event Time: Wednesday, July 28, 2021 | 10:00 am - 11:00 am
Event Location:
Online
Add to Calendar 2021-07-28T10:00:00 2021-07-28T11:00:00 Chemodynamical evolution of galaxies Event Information: Metallicities and elemental abundances are key to testing our current understanding of galaxy formation and evolution. At the beginning of the universe only light elements such as hydrogen and helium were produced. Carbon and heavier elements were instead created inside stars and distributed into the interstellar medium by stellar winds and supernova explosions. From the spatial distribution of elements in stars and gas, it is therefore possible to constrain the star formation and chemical enrichment histories of galaxies. This approach, Galactic Archaeology, has been popularly used for our Milky Way Galaxy. It can also be applied to external galaxies thanks to recent and future observations with integral field spectrographs. A decade ago it became possible to simulate chemical and dynamical evolution of galaxies following the development of high performance computers and improved computational techniques. I will show some recent simulation predictions of mass-metallicity relations and of metallicity radial gradients, and I will discuss future prospects in the era of the James Webb Space Telescope. 2021 BC Galaxy Summer Seminars" is an online seminar series organized jointly by SFU, UBC and UVic. For the full series schedule, visit the series webpage. Subscribe to our e-mail list here to get reminders about these seminars. Event Location: Online
Event Time: Monday, July 26, 2021 | 3:00 pm - 4:00 pm
Event Location:
Connect via zoom
Add to Calendar 2021-07-26T15:00:00 2021-07-26T16:00:00 The Dynamics of Compact, Multi-planet Systems Event Information: The Kepler telescope detected thousands of exoplanets in hundreds of multi-planet systems and revolutionised planetary sciences. Many of these systems are quite compact and are typically a few billions of years old. Consequently, we are seeing only a snapshot of system architectures after hundreds of billions or even trillions of orbits. A substantial portion of their evolution has been governed by dynamical interactions, however. This can allow us to probe their histories and constrain the role of the natal environment. In this talk, I will provide an overview of our present knowledge of these planetary systems and share my work to unravel some of the complexities of their dynamics - a problem as old as astronomy itself. Event Location: Connect via zoom
Event Time: Thursday, July 22, 2021 | 4:00 pm - 5:00 pm
Event Location:
Connect via zoom
Add to Calendar 2021-07-22T16:00:00 2021-07-22T17:00:00 Quantum Gravity in the Lab Event Information: It has long been assumed that gravity and quantum mechanics can only be confronted at very high energies ~ 1.2 x 10^28 eV (enough to boil 5 tons of water, and 15 orders of magnitude above the range of particle accelerators). However, recent theory indicates that gravity may cause a breakdown of quantum mechanics at much lower energies, for large masses. This has led to a new experimental field in which such a breakdown is sought in earth-based labs.     I will review the theory which has made such predictions, and their history, which begins with speculations by Feynman in 1957. I will focus on the Correlated Worldline (CWL) theory, which is the only one so far to make definite quantitative predictions. I will then discuss some of the optomechanical experiments that are trying to test the theory, and where they are right now. These experiments are pushing the boundaries of our understanding of quantum mechanics at the macroscopic scale; as such they have implications for everything from quantum computation to future gravitational wave detectors. Event Location: Connect via zoom
Event Time: Wednesday, July 21, 2021 | 3:00 pm - 4:00 pm
Event Location:
Online
Add to Calendar 2021-07-21T15:00:00 2021-07-21T16:00:00 Quenching massive galaxies Event Information: How and why galaxies grow in stellar mass and cease their star formation are key open questions of galaxy formation and evolution. I present evidence for a diversity of pathways for building up the quiescent galaxy population at early cosmic times. Specifically, I will present observational constraints on star-formation histories and quenching timescales by combining Keck DEIMOS spectroscopic data with >10-band photometry. I will discuss how one can self-consistently fit both photometric and spectroscopic data together with the tool Prospector, which allows fitting for non-parametric star-formation histories and complex stellar, nebular, and dust physics. Despite the apparent diversity, we find that the most massive, compact galaxies have formed their stars the earliest and most rapidly. Furthermore, from the star-formation history constraints, I will discuss how galaxies evolve about scaling relations (such as the star-forming main sequence) with cosmic time. Finally, I will relate these findings to numerical simulations (in particular IllustrisTNG), showing that the large diversity of quenching epochs and timescales challenge numerical models and point toward a combination of internal and external quenching mechanisms. "2021 BC Galaxy Summer Seminars" is an online seminar series organized jointly by SFU, UBC and UVic. For the full series schedule, visit the series webpage. Subscribe to our e-mail list here to get reminders about these seminars. Event Location: Online
Event Time: Monday, July 19, 2021 | 3:00 pm - 4:00 pm
Event Location:
Connect via zoom
Add to Calendar 2021-07-19T15:00:00 2021-07-19T16:00:00 Small But Mighty: The Tiniest White Dwarf and Other Stories Event Information: The advent of Gaia and of large photometric and spectroscopic surveys is changing the landscape of white dwarf studies. These incredible new data sets, together with improved models, have enabled tackling some unsolved mysteries concerning white dwarfs as a population, as well as discovering extremely peculiar objects that challenge our understanding of white dwarf formation and evolution. In my talk, I will show how the precise astrometry from Gaia has dramatically improved our capability of studying white dwarfs in young star clusters, and therefore probe the evolution of white dwarfs born from single progenitor stars. On the other hand, the Zwicky Transient Facility (ZTF) is shedding light on the evolution of white dwarfs in binary systems, substantially increasing the number of known eclipsing white dwarf binaries and finding the final products of such binaries. In fact, ZTF is discovering a large number of massive, rapidly rotating and highly magnetized white dwarfs whose extreme properties characterize them with high confidence as remnants of white-dwarf mergers. Finding a population of white dwarf merger remnants just below the Chandrasekhar mass can help constrain the number of mergers in the Galaxy and their contribution to the type Ia supernova rate, as well as help us understand the origin of strong magnetic fields in white dwarfs. I will present some early results of the search, including the discovery of ZTF J1901+1458, a moon-sized white dwarf that is extreme in almost every respect. Event Location: Connect via zoom
Event Time: Thursday, July 15, 2021 | 4:00 pm - 5:00 pm
Event Location:
Connect via zoom
Add to Calendar 2021-07-15T16:00:00 2021-07-15T17:00:00 Increasing Accuracy in the Hubble Constant: Consistency with LCDM Event Information: An important and unresolved question in cosmology today is whether there is new physics that is missing from our current standard Lambda Cold Dark Matter (LCDM) model. Recent measurements of the Hubble constant, Ho - based on Cepheids and Type Ia supernovae (SNe) - are discrepant at the 4-5-sigma level with values of Ho inferred from measurements of fluctuations in the cosmic microwave background (CMB). The latter assumes LCDM, and the former assumes that systematics have been fully accounted for. If real, the current discrepancy could be signaling a new physical property of the universe. I will present new results based on an independent calibration of SNe Ho based on measurements of the Tip of the Red Giant Branch (TRGB). The TRGB marks the luminosity at which the core helium flash in low-mass stars occurs, and provides an excellent standard candle. Moreover, the TRGB method is less susceptible to extinction by dust, to metallicity effects, and to crowding/blending effects than Cepheid variable stars.   I will address the current uncertainties in both the TRGB and Cepheid distance scales, as well as discuss the current tension in Ho and whether there is need for additional physics beyond the standard LCDM model.     Event Location: Connect via zoom
Event Time: Thursday, July 15, 2021 | 1:00 pm - 3:00 pm
Event Location:
via ZOOM
Add to Calendar 2021-07-15T13:00:00 2021-07-15T15:00:00 Departmental Doctoral Oral Examination (Thesis Title: “The effects of calibration errors and foreground filters on the CHIME power spectrum measurement. A study with simulations and real data.”) Event Information: Abstract: The Canadian Hydrogen Intensity Mapping Experiment (CHIME) is a drift-scan radio telescope designed to map large scale structure in the universe using the redshifted 21 cm line emitted by neutral hydrogen. By observing the 400 to 800 MHz frequency band, CHIME will measure the expansion rate of the universe in the redshift range z = 0.8 - 2.5 to constrain the nature of dark energy. In this frequency range, astrophysical foregrounds from the Galaxy and extragalactic point sources are much brighter than the 21 cm emission. This requires aggressive foreground filtering. We therefore developed a new implementation of the Karhunen-Loeve (KL) transform that correctly tracks the signal and noise power in our data to enable us to filter bright foregrounds. As part of the development of the KL transform, we significantly improved the point source component of the foreground model. The data volumes for CHIME are extremely large, therefore we developed an upgraded parallelized power spectrum estimation pipeline which is able to forecast the Fisher information matrix and estimate power spectra for a telescope almost as large as CHIME. Due to the bright astrophysical foregrounds CHIME has very stringent calibration requirements.  We wrote an end-to-end simulation pipeline and studied various realistic sources of calibration uncertainties with it. The calibration requirements are very stringent and we found that CHIME currently doesn't quite meet the requirements when using the Karhunen-Loeve (KL) foreground filter. We must therefore continue to develop innovative foreground filters that are more robust against systematics and we must explore further whether our requirements are too conservative or if a larger telescope will allow us to relax these requirements. We then investigated different processing choices on power spectrum estimation with CHIME data in the frequency band 610 to 680 MHz with a selection of short baselines to ensure quick computation times. We found the even with our currently best calibration procedures our power spectrum estimates are several orders of magnitude higher than expectation. Using a delay filter as an intermediate processing step seemed to reduce the bias but we leave further development of a hybrid filter to future work. Event Location: via ZOOM
Event Time: Wednesday, July 14, 2021 | 10:00 am - 11:00 am
Event Location:
Online
Add to Calendar 2021-07-14T10:00:00 2021-07-14T11:00:00 Dwarf Galaxies and Their Black Holes Event Information: Because they are dark-matter dominated, dwarf galaxies provide some of the most stringent tests of our cold dark matter model. Specifically, Lambda CDM makes predictions about the number, shape, and spatial distributions of the faint friends of massive galaxies. I will present results from the Exploration of Local VolumE Satellites (ELVES) survey, that constructs the largest sample of satellites around Milky Way-like hosts. Our ability to utilize dwarfs as tests of CDM is limited by our understanding of baryonic process; I will also discuss our efforts to us the Hyper Suprime Camera Survey to understand the role of feedback and merging in dwarf evolution. If time permits, I discuss what we know about black holes in dwarf galaxies, and how their demographics sheds light on the formation of the seeds of supermassive black holes. "2021 BC Galaxy Summer Seminars" is an online seminar series organized jointly by SFU, UBC and UVic. For the full series schedule, visit the series webpage. Subscribe to our e-mail list here to get reminders about these seminars. Event Location: Online
Event Time: Wednesday, July 14, 2021 | 9:00 am - 11:00 am
Event Location:
via ZOOM
Add to Calendar 2021-07-14T09:00:00 2021-07-14T11:00:00 Departmental Doctoral Oral Examination (Thesis Title: “Learning Physics with Interactive Simulations: Inductive Inquiry Learning Activities for an Introductory Electromagnetism Course”) Event Information: Abstract: In this work, the use of interactive simulations in the context of an inductive learning pedagogical approach in the tutorials of a large enrollment introductory electromagnetism course is investigated. Interactive simulations are educational tools that allow students to uncover the rules that govern a simulated physics phenomenon through a process of scientific inquiry. These simulations can be designed with affordances and constraints that implicitly scaffold inquiry such that students can more efficiently uncover important features of the simulated phenomenon. As such, interactive simulations are a promising tool to use in the context of invention activities, where students invent a rule for a target physics domain before receiving any formal instruction on it. We report the results of a study comparing the educational benefits of invention activities where students invent a rule either by generating their own cases from a simulation or from a set of contrasting cases designed to directly highlight important domain features when compared to one another. The simulation-based invention activities provide students with an opportunity to practice and develop valuable exploration skills but the greater agency in their exploration can also makes it harder to successfully explore all important domain features. This thesis details the design of a series of three collaborative and scaffolded practice invention activities that aim to mitigate this issue. Results show that generating cases from a simulation in these activities is less likely to lead students to invent the correct rule and generally leads to poorer immediate conceptual learning outcomes as compared to using instructor designed contrasting cases. Results also demonstrate that a student's ability to explore and identify all important features of the target rule is largely determined by how well the instructional material provided affords the investigation of those features. Finally, the above student outcomes are also compared across two final assessment invention activities where students worked individually without scaffolding; in the first students invent by generating their own cases from a simulation, while in the other they use instructor-design contrasting cases. We show that students that had previously practiced inventing with contrasting cases performed the same or better on all outcomes compared to those that practiced inventing by generating cases from a simulation. Event Location: via ZOOM
Event Time: Monday, July 12, 2021 | 3:00 pm - 4:00 pm
Event Location:
Connect via zoom
Add to Calendar 2021-07-12T15:00:00 2021-07-12T16:00:00 Galaxies, AGN and their environments Event Information: A key open question in extragalactic astronomy is understanding the processes driving the build-up and quenching of massive galaxies — specifically the role of AGN and environment therein. As an overview of my recent research activities, I will present several projects that all help inform the above question.  I will address some of the issues with going from observed properties to physical properties and a possible pathway to scaling this up to the sample sizes in the billions that are on our horizon now.  In this context, I will touch upon the issue of fully accounting for dust obscured star-formation and AGN activity. Lastly, I will discuss how we assess a galaxy's environment with photometric data as well as prospects for doing so much better with the upcoming PFS galaxy evolution spectroscopic survey.  Event Location: Connect via zoom
Event Time: Friday, July 9, 2021 | 10:00 am - 12:00 pm
Event Location:
Virtual
Add to Calendar 2021-07-09T10:00:00 2021-07-09T12:00:00 Impostor Syndrome Workshop Event Information: The Equity & Inclusion in PHAS team presents “Impostor Syndrome,” a workshop run by astrophysicist Dr. Renée Hložek. Navigating the academic environment can be stressful. Power dynamics can impact our ability to communicate clearly with each other, and can generate feelings of impostor syndrome. In this interactive workshop, we will use techniques of improvisation and changing power dynamics to explore ways we can shape our communication environment. The session will include a short presentation, followed by a group discussion and an interactive component with improvisation exercises. It is open to people of all academic stages who are keen to think about these topics in new ways, and to try new techniques to help make our work environment a more comfortable space. Date: Friday, July 9th, 10:00am – 12:00pm PDT via Zoom Please register by Wednesday, July 7th. This workshop is free! Register: https://ubc.zoom.us/meeting/register/u5ctd-yoqzguGNMUiGhsN7Z-iNFp_rm4NpBu Event Location: Virtual
Event Time: Thursday, July 8, 2021 | 4:00 pm - 5:00 pm
Event Location:
Connect via zoom
Add to Calendar 2021-07-08T16:00:00 2021-07-08T17:00:00 Fractional derivatives and applications in MRI Event Information: Diffusion-weighted Magnetic Resonance Imaging (MRI) Depicts Regions of Sub- and Super-diffusion Encoded by the Fractional Diffusion Equation Fractional-order time and space derivatives extend the classical diffusion equation in a manner that accounts for the non-Gaussian diffusion often observed in heterogeneous materials. MRI provides diffusion-weighted images of biological tissues, which exhibit anisotropic, hindered, and restricted diffusion. Fractional calculus models of anomalous diffusion display regions of sub- and super-diffusion separated by a line of quasi-diffusion along which the mean squared displacement is a linear function of diffusion time. This behavior can be captured by fractional derivatives and/or by introducing a diffusion coefficient with a power-law decay varying as a function of time or space. The corresponding phase diagrams, like pages in a book, result in a portfolio of representations of anomalous diffusion. The anomalous phase cube employs lines of super-diffusion (Lévy process) and sub-diffusion (subordinated Brownian motion) to stitch together the different diffusion models for corresponding regions. Event Location: Connect via zoom