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  • Physics Colloquium – Ronan Humphrey

    Chemistry 108 2050 E Kenwood Blvd, Milwaukee, WI, United States

    Physics Colloquium - Ronan Humphrey, UWM Physics
    Presentation title and abstract will be announced when they are available.

  • Physics Colloquium – Eitan Geva

    Chemistry 108 2050 E Kenwood Blvd, Milwaukee, WI, United States

    Combining 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 Arbor

    Photo-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 States

    Black Holes: Bridging Simulations and Observations
    León Salas
    University of Wisconsin-Milwaukee

    In 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*.

  • Physics Colloquium – Adam Opperman

    Kenwood IRC 2035 3135 N Maryland Ave, Milwaukee, United States

    Manifold-based Machine Learning for Scattering Data
    Adam Opperman, PhD Candidate
    University of Wisconsin-Milwaukee Department of Physics & Astronomy

    Small 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.

  • CGCA Seminar – Tyler Trent

    Kenwood IRC 2175 Milwaukee, WI, United States

    Ohana Kilo Hoku: Hawaiian Culture Based Astronomy Outreach
    Tyler Trent
    University of Maryland

    Astronomy 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.

  • Physics Colloquium – Jong-Woo Kim

    Chemistry 108 2050 E Kenwood Blvd, Milwaukee, WI, United States

    Studying Magnetism with Resonant X-ray Scattering at Advanced Photon Source
    Jong-Woo Kim, Physicists
    Magnetic Material Group/Advanced Photon Source, Argonne National Laboratory

    X-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.

  • CGCA Seminar – Reshma Anna Thomas

    Kenwood IRC 2175 Milwaukee, WI, United States

    Low-Frequency Radio Transients
    Reshma Anna Thomas
    Netherlands Institute for Radio Astronomy, University of Amsterdam

    The 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.

  • Physics Colloquium – Sarah Villanova Borges

    Chemistry 108 2050 E Kenwood Blvd, Milwaukee, WI, United States

    Constraining Common Envelope Evolution Simulations with Observations
    Sarah Villanova Borges, PhD Candidate
    University of Wisconsin-Milwaukee

    Common 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.

  • CGCA Seminar – Janeth Valverde

    Kenwood IRC 2175 Milwaukee, WI, United States

    Title and abstract to be determined
    Janeth Valverde
    Marquette University

    The abstract for this talk will be added as soon as it is made available.

  • Physics Colloquium – Nicholas Stone

    Chemistry 108 2050 E Kenwood Blvd, Milwaukee, WI, United States

    Gravitational Waves from Galactic Nuclei
    Nicholas Stone, Assistant Professor
    Department of Astronomy, University of Wisconsin-Madison

    The discovery of GW150914 inaugurated the era of gravitational wave (GW) astronomy, opening a new window to study our Universe's compact objects and through which to test general relativity. Now, a decade later, the LIGO-Virgo-KAGRA (LVK) collaboration has seen hundreds of GW signals, overwhelmingly from mergers of binary stellar mass black holes. Despite the many successes of GW astronomy, a zeroth-order astrophysical question remains unanswered: what astrophysical environments produce the LVK binary black holes, and by what process are they assembled? Although many formation channels have been proposed, one uniquely testable solution is the "AGN channel:" a scenario in which individual black holes pair up and merge in the dissipative gaseous environment of an active galactic nucleus.