Events
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CGCA Seminar – Debatri Chattopadhyay
Kenwood IRC 2175 Milwaukee, WI, United StatesNeutron Star–Black Hole Binaries: Predictions and Observations
Debatri Chattopadhyay
Northwestern UniversityNeutron star–black hole (NS–BH) binaries have emerged as key targets for multi-messenger astrophysics following the first gravitational wave detections of such systems. In this talk, I present population synthesis predictions for the Galactic NS–BH population, models that interpret the first observed mergers, and forecasts for future radio, gravitational-wave, and electromagnetic discoveries.
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CGCA Seminar – Kenzie Nimmo
Kenwood IRC 2175 Milwaukee, WI, United StatesUnraveling the origins of fast radio bursts and using them as probes of extreme plasmas
Kenzie Nimmo
Northwestern UniversityFast radio bursts (FRBs) are millisecond-duration flashes of coherent radio emission originating from extragalactic distances, offering a unique view into the physics of compact objects and their surrounding environments. Despite their brief and unpredictable nature, precise localizations of a small number of FRBs have already revealed a striking diversity in host galaxies, local environments, and burst properties - suggesting multiple progenitor channels linked to extreme compact objects. However, the nature of FRB sources remains one of the most exciting mysteries in astrophysics.
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Physics Colloquium – Ronan Humphrey
Chemistry 108 2050 E Kenwood Blvd, Milwaukee, WI, United StatesPhysics Colloquium - Ronan Humphrey, UWM Physics
Presentation title and abstract will be announced when they are available. -
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Physics Colloquium – Eitan Geva
Chemistry 108 2050 E Kenwood Blvd, Milwaukee, WI, United StatesCombining Quantum Master Equations with Linearized Semiclassical Methods to Simulate Electronic Energy & Charge Transfer Dynamics in Complex Molecular Systems
Professor Eitan Geva, Department of Chemistry
University of Michigan - Ann ArborPhoto-induced electronic energy and charge transfer plays a key role in a variety of chemical, biological and technologically-important molecular systems. The simulation of the
underlying electronic dynamics is challenging due to its intrinsically quantum mechanical nature and the large number of coupled electronic and nuclear degrees of freedom involved. Quantum master equations provide a flexible and general-purpose framework for addressing this challenge. -
CGCA Seminar – León Salas
Kenwood IRC 2175 Milwaukee, WI, United StatesBlack Holes: Bridging Simulations and Observations
León Salas
University of Wisconsin-MilwaukeeIn recent years, General Relativistic Magnetohydrodynamic (GRMHD) simulations, combined with multiwavelength observations have provided critical insights into the nature of radiation from accreting black holes. These simulations have revealed a particularly interesting magnetically arrested disk (MAD) regime whereby the accretion is choked by strong magnetic fields. The higher magnetic flux characteristic of the MAD regime leads to new dynamics, including interchange-type accretion modes and flux eruptions. Polarization measurements by the Event Horizon Telescope (EHT) from the supermassive black holes M87* and Sagittarius A* (Sgr A*) favor MAD states. However, nearly all MAD models exhibit greater 230 GHz flux variability than seen in historical observations of Sgr A*.
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Physics Colloquium – Adam Opperman
Kenwood IRC 2035 3135 N Maryland Ave, Milwaukee, United StatesManifold-based Machine Learning for Scattering Data
Adam Opperman, PhD Candidate
University of Wisconsin-Milwaukee Department of Physics & AstronomySmall Angle X-ray Scattering (SAXS) is a technique used to capture X-ray diffraction images of proteins in solution, mimicking biological conditions. These images provide insight into the overall shape and structure of the protein. By imaging the protein system at various times during a reaction, dubbed time-resolved SAXS (TR-SAXS), the evolution of the protein structure is observed. These measurements are commonly taken at X-ray Free Electron Laser (XFEL) facilities which generate X-rays with precision and high flux. The Compact X-ray Light Source (CXLS) and accompanying Compact X-ray Free Electron Laser (CXFEL) are under construction at Arizona State University. Due to the compact nature of the source in combination with the yet incomplete development, CXFEL has a reduced level of photon flux available compared to other XFELs. Due to this constraint, new analytical methods are needed to process TR-SAXS data.
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CGCA Seminar – Tyler Trent
Kenwood IRC 2175 Milwaukee, WI, United StatesOhana Kilo Hoku: Hawaiian Culture Based Astronomy Outreach
Tyler Trent
University of MarylandAstronomy in Hawaii has become highly controversial in recent years, with construction of new telescopes on Mauna Kea drawing large protests from the local communities, especially Native Hawaiians. As someone who was born and raised on the island of Oahu in Hawaii, and has Native Hawaiian ancestry, I share my perspective on the conflict and present on the work of Ohana Kilo Hoku, a Native Hawaiian non-profit organization I am a member of. Drawing inspiration from ancient Native Hawaiian's who used the night sky to navigate the Pacific Ocean, we work to cultivate relationships between the youth and the science of the sky above.
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Physics Colloquium – Jong-Woo Kim
Chemistry 108 2050 E Kenwood Blvd, Milwaukee, WI, United StatesStudying Magnetism with Resonant X-ray Scattering at Advanced Photon Source
Jong-Woo Kim, Physicists
Magnetic Material Group/Advanced Photon Source, Argonne National LaboratoryX-ray scattering at synchrotron facilities such as the Advanced Photon Source provides a powerful platform for investigating magnetic order with element and orbital specificity. In this colloquium, I will introduce the fundamentals of single-crystal X-ray diffraction and the principles of resonant elastic X-ray scattering (REXS), emphasizing how tuning to absorption edges enhances sensitivity to electronic and magnetic structures.
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CGCA Seminar – Reshma Anna Thomas
Kenwood IRC 2175 Milwaukee, WI, United StatesLow-Frequency Radio Transients
Reshma Anna Thomas
Netherlands Institute for Radio Astronomy, University of AmsterdamThe low-frequency radio sky (<300 MHz) remains comparatively underexplored for fast and slow transients (~ microseconds to minutes), primarily due to strong propagation effects as well as instrumental challenges. However, this regime provides unique leverage on plasma environments and emission physics that are inaccessible at GHz frequencies. Fast radio bursts (FRBs) are extragalactic coherent transients with millisecond durations, often exhibiting sub-millisecond temporal structure. I will present detections of two FRBs at 150 MHz using beamformed searches with LOFAR, which place some of the most stringent constraints to date on free–free absorption in their local environments. In parallel, a new class of Galactic sources, long-period transients (LPTs), has recently emerged, characterized by emission on second-to-minute durations and periodicities spanning minutes to hours.
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Physics Colloquium – Sarah Villanova Borges
Chemistry 108 2050 E Kenwood Blvd, Milwaukee, WI, United StatesConstraining Common Envelope Evolution Simulations with Observations
Sarah Villanova Borges, PhD Candidate
University of Wisconsin-MilwaukeeCommon Envelope Evolution (CEE) remains one of the biggest unresolved problems in binary stellar evolution, despite being the primary pathway for the formation of close binary systems. One of the main challenges in understanding CEE is its intrinsically multiscale and multiphysics nature, which makes it difficult to model with analytical or 1D models. 3D hydrodynamical simulations have therefore become essential tools for studying this phase. However, validating these simulations requires observational constraints, which are scarce. This lack of direct observations is another major obstacle in modeling CEE. One exception is luminous red novae, which is believed to correspond to CEE events that culminate in stellar mergers.