Three-Minute Thesis Competition
BYU Physics & Astronomy Students
Friday, January 24, 12:00 PM, C215 ESC
Precision Black Hole Mass Measurements in the ALMA Era
Physics & Astronomy, Texas A&M University
Friday, January 31, 12:00 PM, C215 ESC
Abstract: While supermassive black holes (BHs) gravitationally dominate only the innermost regions of galaxies, their masses correlate with large-scale galaxy properties, demonstrating the co-evolution of BHs and host galaxies over the age of the universe. These correlations suggest a distinct evolutionary pathway for the most luminous galaxies; however, an incomplete census of >10^9 solar mass BHs (and large measurement uncertainties) preclude any definitive conclusions. Emission-line observations with the Atacama Large Millimeter/submillimeter Array (ALMA) are opening a new avenue for studying BH demographics in nearby galaxies. I will present ongoing ALMA CO imaging that has resolved circularly-rotating molecular gas disks in the nuclei of a growing number of very luminous galaxies, providing ideal probes of their inner gravitational potentials. I will highlight results from recent gas-dynamical modeling efforts, which have enabled some of the most precise direct BH mass determinations to date, and discuss the prospect of future telescopes like the next-generation Very Large Array (ngVLA) to expand on ALMA's revolutionary capabilities.
Biographical Sketch: After graduating from Brigham Young University with a BS in Physics & Astronomy in 2012, Benjamin Boizelle pursued graduate studies at the University of California, Irvine, earning MS and PhD degrees in Physics and Astronomy. During these years, he also taught introductory astronomy courses at nearby Santa Ana College. In 2018, he began working with Professor Jonelle Walsh at Texas A&M University as a postdoctoral researcher. In addition to black holes, Dr. Boizelle's research interests include active galaxies, dust attenuation, and transient astronomical phenomena.
Giant Impacts, Astrochemistry and the First Water in the Universe
Southern Utah University
Monday, February 3, 12:00 PM, C215 ESC
Abstract: It is now believed that as much as 50% of the solar system’s water may have predated the Sun, suggesting an ancient heritage for this life-giving substance. This raises questions about the abundance of water throughout the universe, and touches on the question of the cosmic conditions in which this ingredient for the rise of life first appeared. In this talk, I will summarize efforts, now 4 years in the making and spanning 5 institutions, to create the first simulation of the rise of water in the early universe. We couple a fully implicit chemical reaction network, including 50 reactants and now 350 reactions, inline with an Eulerian cosmology code. I’ll present state-of-the-art visualizations of our initial simulation results of water appearing in its first cosmological context in the very early universe and will discuss implications of our results. In addition, I’ll also briefly provide a quick survey of some of my other LANL-based initiatives, including efforts this past summer to couple sophisticated chemistry solvers with particle hydrodynamic simulations of giant impacts in planets and recent results from combining cosmology codes to population synthesis models of stellar evolution to predict circum-burst densities and visual offsets of merging binary neutron stars from their host galaxies in the cosmic web.
Biographical Sketch: Brandon Wiggins has been an Assistant Professor of Physics at Southern Utah University (SUU) and a consulting scientist at Los Alamos National Laboratory (LANL) since 2016. He obtained his bachelor’s degree from Southern Utah University and a doctorate from Brigham Young University, and completed dissertation research full-time on-site at LANL (2015-2016). Brandon spends his summers at the Center for Theoretical Astrophysics at LANL, where he works on cosmology, double neutron-star mergers, supernova light curves and planetary-science thrusts, and where he has mentored 19 undergraduate research students from SUU and BYU. He specializes in high-performance computing modeling in astrophysics in areas of astrochemistry, particle and Eulerian hydrodynamics, and radiative transfer. He led a collaboration between LANL, UT Austin, Southern Utah University, and ASC, which created 3D visualizations of large-scale astrochemistry simulations of the early universe. This work won 2nd place world-wide in the category for Best Scientific Visualization of 2018. Brandon was recognized by Utah Lt. Gov. Spencer Cox for his extensive volunteer science-outreach efforts throughout southern Utah. He has also received many honors at SUU for influencing students inside the classroom, including the university’s top teaching honor, which was received during his first year there. He is passionate about communicating science in accessible ways, and has written a 450 page introductory physics textbook. He is currently preparing a manuscript that introduces cosmology to undergraduates who have little background in coding, physics or HPC. Brandon and his wife parent 4 children and enjoy hiking, Star Wars, traveling, the Lord of the Rings, and sushi.
Exploring the Low Surface Brightness Universe
RAS Central (Pulkovo) Observatory, Saint Petersburg, Russia
Friday, February 14, 12:00 PM, C215 ESC
Abstract: Despite of the wealth of observational data due to multiple full or partial-sky surveys, the low surface brightness Universe remains almost completely unexplored. In the last decade there has been significant progress in developing optical systems, detector technology, clever observational strategies, and data reduction techniques, to obtain deep imaging of very good quality. While the Dragonfly survey has attained success, they have done so with a system that is costly in capital and operation. In this talk I will present our new results in low surface brightness imaging. Using two dedicated 0.7m telescopes in California and Wise Observatory, Israel, we are able to study very faint details (tidal tails and streams, plums, bridges, envelopes) around nearby galaxies. We pay special attention to describing the outer shapes of galaxies viewed edge-on. The outer envelopes of edge-on galaxies fall into three broad categories: diamond-like, oval or boxy. We connect this appearance to the merger history and its intensity in the past and present. Also, we exploit our deep observations to search for low surface brightness and ultra-diffuse, extremely faint galaxies. In addition to that, we show that diffuse light in compact groups and clusters of galaxies can be used as a tracer of the dark matter distribution in dark matter halos. I will describe an ambitious project to map the low surface brightness Universe using existing optical sky surveys which will shed more light on the dark side of our Universe. These data will ultimately be compared with predictions of galaxy formation models based on the dominant LCDM paradigm.
Biographical Sketch: Alexander Mosenkov is a senior researcher at the Department of Celestial Mechanics and Dynamical Astronomy of the Central (Pulkovo) Observatory of the Russian Academy of Sciences in Saint Petersburg, Russia, and a lecturer at Saint Petersburg State University. He received a B.Sc. with Honors in astronomy in 2008 from Saint Petersburg State University, and a Ph.D. in astrophysics from the same university in 2013. He was a post-doctoral researcher for Ghent University, Belgium, in 2015-2017. He has authored/co-authored over 50 scientific publications that include a broad range of international collaborators. He is a leading researcher of the DustPedia collaboration aimed at a definitive study of dust in galaxies. In 2018, he was elected a member of the International Astronomical Union. His research interests are in the area of galaxy formation and evolution. They encompass studying structural properties of galaxies (including the Milky Way), galaxy scaling relations, numerical simulations of galaxies, and panchromatic simulations of galaxies with a complex interstellar medium using radiative transfer codes. He develops his own software for different astrophysical tasks. He holds a Russian Foundation grant for a comprehensive study of spiral structure in galaxies. One of his recent interests is exploring the low surface brightness Universe: Dr. Mosenkov is a senior member of the Halos and Environments of Nearby Galaxies (HERON) survey (PI, Prof. Michael Rich, UCLA). Since 2016, he has supervised four undergraduate students and three PhD students and was a referee of many masters and PhD theses. He has received three Struve awards from the Pulkovo Observatory for the best annual research as a young researcher. Recently, he was nominated by the Pulkovo Observatory for a presidential award as the best young scientist of Russia, for his contribution in studying dust in the Universe.
We welcome anyone who wish to attend, and typically serve refreshments ten minutes before the colloquium begins. Speakers generally keep their presentation accessible to undergraduate physics students.