- Friday Science Discussion Groups -
"Reminiscences and the opinion of an aging astronomer about what's most important in astronomy today." Frank N. Bash, Ph.D.
Dr. Bash has always been amazed at what astronomy appears in the news. The most important things — in his opinion — are never mentioned. In this SDG, Dr. Bash will also comment on the vital role the Board of Visitors has played in the astronomy program at Texas.
"'HETDEX' has started, an update on the science and experiment." Karl Gebhardt, Ph. D.
The McDonald Observatory and Department of Astronomy has begun its observing campaign for HETDEX. All indications are that we are at specification and will produce strong constraints on the evolution of dark energy. There have been recent advances in observational measures of dark energy. In this SDG, Dr. Gebhardt will place HETDEX in context with all current observations. This is a very exciting time for HETDEX! It is finally happening!
"How Do We Detect Dark Stuff?" Eva Noyola, Ph. D.
When Dr. Noyola says, “dark stuff” she means dark matter and compact objects. She’s not a cosmologist so she won’t deal with dark energy. Dr. Noyola has an ongoing large observational project at the McDonald Observatory working with dark matter and extensive experience in the detection of compact objects. This talk will connect the McDonald Observatory’s current work and resources with potential observations using the resources of the Giant Magellan Telescope.
"First Light with the James Webb Space Telescope" Steve Finkelstein, Ph. D.
The James Webb Space Telescope, launching in Spring 2019, will be NASA’s successor to the Hubble Space Telescope. With a mirror size seven times greater than that of Hubble, and reaching far into the infrared, Webb will transform nearly every area of astrophysics, from directly imaging planets around other stars, to peering into dusty star-forming regions in our own galaxy, to discovering some of the first galaxies to form in the early universe. The Space Telescope Science Institute, which operates Hubble and will run Webb, recently solicited proposals for the first observations to be done with Webb. Out of 106 proposals submitted, 13 “Early Release Science” programs were accepted, with five of the 13 including UT Austin astronomers as participants. Dr. Finkelstein will talk about one of these proposals, the Cosmic Evolution Early Release Science (CEERS) Survey, for which he is the Principal Investigator, and includes ~10 UT faculty, postdocs and grad students. CEERS will observe extremely distant galaxies with several Webb instruments, discovering the most distant galaxies ever seen, hailing from a time when the universe was only 3% of its current age, and will use spectroscopy to obtain the first-ever detailed physical measurements of such distant galaxies.
- Friday Dinner Keynote -
"Gravitational Radiation: A New Window into the Universe" Pawan Kumar & J. Craig Wheeler
Abstract: Einstein's 100-year-old theory of the workings of space-time came to remarkable fruition in September 2015 when the Laser Interferometer Gravitational-Wave Observatory (LIGO) detected the gravitational-wave "chirp" (or ripple in space-time) of two orbiting, merging black holes from a billion light years away. This discovery, awarded the 2017 Nobel Prize in Physics, also culminated a three-decade effort of incredible engineering sophistication to measure tiny motions, smaller than a proton, in the detectors and a parallel 30-year effort to solve Einstein's equations on a computer, the roots of which were in the University of Texas Center for Relativity. This discovery was rapidly followed by three other confirmed black hole merger events and then in August 2017 the merger of two neutron stars from about 130 million light years away. This event made optical light in addition to gravitational waves and follow up observations of this catastrophic event were made using several dozen telescopes by 4000 astronomers around the world, once again confirming years of theoretical work predicting the nature and outcome of neutron star mergers, including the origin of gold and uranium. We will relate both the scientific and human stories behind this dramatic development and the impact it will have on the study of our dynamic universe and on graduate research at UT.
J. Craig Wheeler is the Samuel T. and Fern Yanagisawa Regents Professor of Astronomy, Distinguished Teaching Professor at the University of Texas at Austin, and past Chair of the Department. His research interests include supernovae, black holes, astrobiology. and the technological future of humanity. He has published over 350 refereed scientific papers and co-authored a recent book, Supernova Explosions. He has also written a popular book on supernovae and gamma-ray bursts, Cosmic Catastrophes, two novels, and has edited six books. Wheeler has received many awards for his teaching, including the Regents Award, and is a popular science lecturer. He was a visiting fellow at the Joint Institute for Laboratory Astrophysics (JILA), the Japan Society for the Promotion of Science, the Cerro Tololo Interamerican Observatory, and a Fulbright Fellow in Italy. He has served on many agency advisory committees, including those for the National Science Foundation, the National Aeronautics and Space Administration, and the National Research Council. He has held many positions in the American Astronomical Society and was President of the Society from 2006 to 2008. He currently serves on the AAS Ebooks Board and on the Ethics Committee.
Pawan Kumar is a Professor of Astronomy at the University of Texas at Austin. He has made fundamental contributions to the theory of solar and stellar pulsations, exploding stars (gamma-ray bursts) and other transient phenomena. Prior to joining UT Austin he held faculty positions at the Institute for Advanced Study, Princeton and MIT. He is a recipient of Sloan and NSF Young Investigator awards.
- Saturday Science Talks -
Graduate Student Talk
"Big Data, Big Opportunities: Exploring Galaxy Evolution in the Colossal HETDEX/SHELA Field" Sydney Sherman
Abstract: Observations and theoretical models suggest that the most massive galaxies in the universe formed the majority of their stars in the first three billion years after the Big Bang, and have formed few, if any, stars since. Until now, observational studies have only discovered dozens of these rare, massive objects due to the small areas of the sky that they observed. The immense area of the HETDEX/SHELA survey is an order of magnitude larger than preceding studies, providing the unprecedented opportunity to find statistically significant samples of extremely massive galaxies. With the discovery of an enormous sample of these elusive objects, we aim to answer the important question of how such massive galaxies could form at such early times.
Sydney Sherman is a third-year graduate student working with Dr. Shardha Jogee to investigate how galaxies evolve when the universe was only a few billion years old. In 2015, she earned her B.S. in Astronomy from The Pennsylvania State University. In addition to her academic pursuits, Sydney is involved in community outreach projects and was elected to serve as the Astronomy Department Graduate Representative for the 2017-2018 academic year.
Postdoctoral Fellow Talk
"Using Artificial Intelligence to Find the Number of Earth-like Planets in our Galaxy" Andrew Vanderburg, Ph.D.
Abstract: A major goal of astronomers is to robustly measure the frequency of Earth-sized planets in Earth-like temperate orbits in our galaxy, but currently our best observations, four years of data from NASA's Kepler mission, are not quite sensitive enough to achieve this goal. My team and I are working to improve the sensitivity of Kepler's observations using deep neural networks - one of the most exciting new techniques in the field of artificial intelligence today. I will present our first results from this work, a proof-of-concept neural net which we have used to discover an exciting new exoplanet. I will conclude by describing our plans to take this work full scale and use it, along with observations from McDonald Observatory, to find how common potentially Earth-like planets are and put our own Earth in its galactic context.
Dr. Andrew Vanderburg is a NASA Sagan Postdoctoral Fellow at The University of Texas at Austin. He studies exoplanets which transit their host stars -- that is, planets whose orbits around other stars are aligned so that they pass in front of their star as seen from Earth. He is interested in what transiting exoplanets can reveal about the origins and characteristics of the planets throughout the galaxy. Vanderburg earned his Ph.D. in Astronomy and Astrophysics from Harvard University in 2017.
Faculty Talk
“Harnessing Machine Learning to Study the Life Cycle of Stars” Stella Offner, Ph.D.
Abstract: Neighboring forming stars strongly influence each other and their natal molecular cloud by injecting energy into their surroundings via radiation, winds and jets (“feedback"). However, identifying this feedback and disentangling its interaction with the environment “by eye" is challenging, time-consuming and subjective. Machine learning, a sub-field of computer science in which algorithms can learn and evolve without explicit programming, provides a powerful alternative to visual identification. In this talk I will discuss how a combination of state-of-the-art numerical simulations together with machine learning can be used to identify and study features created by stellar feedback.
Dr. Stella Offner received bachelor’s degrees in physics and mathematics from Wellesley College in 2003, and a Ph.D. in physics from the University of California at Berkeley in 2009. From 2009-2012 she was an NSF Astronomy & Astrophysics prize postdoctoral fellow at the Harvard-Smithsonian Center for Astrophysics and a NASA Hubble prize postdoctoral fellow at Yale from 2012-2014. Before joining the astronomy faculty at UT Austin in 2017, she was an assistant professor at the University of Massachusetts Amherst. Offner's research focuses on understanding how stars like the Sun form by combing numerical simulations, observations and observational modeling.
- Great Lecture -
"From the Telescope to the Laboratory and Back Again: the Center for Astrophysical Plasma Properties" Don Winget and Mike Montgomery
Abstract: The core principle of the Center for Astrophysical Plasma Properties (CAPP) is to do "at-parameter" experiments under astrophysical conditions of stars and accretion disks—making astronomy an experimental science. We have designed initial experiments to address stellar opacities, line-broadening, and the physics of accretion disks around black holes. We plan to expand the suite of experiments to other astrophysical environments. This Center will bring to the department full support for five graduate students. CAPP will also support two postdocs in the astronomy department. Also involved in CAPP as Co-Investigators are Craig Wheeler and incoming faculty member Keith Hawkins. Each will work with a graduate student involved in the intersection of astronomy and experimental astrophysics. We will discuss the impact of this on the UT Astronomy Program.
Dr. Mike Montgomery is a Research Scientist in the Department of Astronomy working on stellar astrophysics. His work focuses on the evolution and pulsation of white dwarf stars, and on laboratory experiments that directly test stellar physics. He received his Ph.D. in astronomy from the University of Texas, and held postdoctoral positions in Vienna and Cambridge before returning to the University of Texas in 2004.
Don Winget has an undergraduate degree in physics from the University of Illinois, and a master’s degree and Ph.D. in physics and astronomy from the University of Rochester. Don is the Harlan J. Smith Centennial Professor of Astronomy and a University Distinguished Teaching Professor. In 1982, during his first year at the University of Texas, Don predicted and discovered a new class of pulsating variable stars. This was the first time in the 300-year-old field of pulsating variable stars that anyone had predicted a new class of pulsating variable stars before their discovery. In 1985, he made the first direct measurement of stellar evolution. In 1987, he developed a new method for measuring the age and assembly history of the Galaxy, currently the most accurate method for dating the stellar components of the galaxy. Winget co-founded, with Prof. R.E. Nather, the Whole Earth Telescope (WET), which uses a network of the major optical observatories around the planet working together to defeat dawn: the sun never rises on the Whole Earth Telescope. Don and his research group use their observations of pulsating white dwarfs to do extreme physics, constraining masses of theoretically proposed particles – such as axions and plasmon neutrinos. This work will help explore the physical nature of dark matter. Don and his collaborators have used the Hubble Space Telescope observations of globular clusters to demonstrate that the dense Coulomb plasma in white dwarf stars crystallize and release latent heat in the process. He is currently involved in a project at Sandia National Laboratories to reproduce the conditions at the surfaces of white dwarf stars in the laboratory, thereby dramatically improving our understanding of these fundamental stellar objects: From Telescope to Laboratory and Back. This is the subject of his talk.