FREE RAS March Ordinary Meeting In-Person or Online Ticket
From High-Redshift Precursors to Present-Day Galaxies: A New Frontier in Astronomy with Graph Neural Networks
Dr Yuan-Sen Ting (Associate Professor at the Australian National University.)
One of the fundamental inquiries in contemporary astronomy concerns the origins and evolution of galaxies. To this end, astronomers have developed various models, often based on human heuristics, to analyze the history of galaxy mergers and gain insight into their properties. However, these traditional methods tend to oversimplify the problems, such as the intricate relationship between galaxies and dark matter haloes. Fortunately, advances in machine learning, especially in graph neural networks, have revealed new avenues of exploration. A graph is a visual representation of the connections between objects, making it a natural tool for analyzing the precursor systems that lead to the formation of galaxies. By utilizing generative graph neural networks, we can probabilistically relate these high-redshift progenitor systems to current-day observations. This innovative approach also holds the potential to identify anomalies in galaxy formation and uncover subtle correlations between precusor features. Through these developments, we aspire to come one step closer to comprehending the rich history and evolution of galaxies.
Yuan-Sen is an Associate Professor at the Australian National University, jointly affiliated with the astronomy and computer science departments. His research endeavors revolve around the utilization of machine learning in advancing statistical inferences, specifically utilizing vast astronomical survey data. Hailing from Malaysia, Yuan-Sen was awarded a PhD in astronomy and astrophysics from Harvard University in 2017, and was subsequently granted a four-way fellowship from Princeton University, Carnegie Institute for Sciences, NASA Hubble, and the Institute for Advanced Study at Princeton. In recognition of his pioneering work in AI x Science, he was acknowledged as a Future Leader by the Association of Universities for Research in Astronomy, in addition to being honored as a NASA Earth and Space Science Fellow. Recently, Yuan-Sen received the ARC DECRA fellowship following his induction to ANU.
In parallel to his academic pursuits, Yuan-Sen assumes the role of co-chair for the NASA Cosmic Programs Stars Science Interest Group, spearheading multiple future spectroscopic surveys as a science group leader. Beyond academia, Yuan-Sen is fervent about public outreach and has authored monthly columns in the largest Chinese newspaper in Malaysia, as well as producing two TED education videos with over 4 million views. Moreover, he has served as a chief science officer developing tools using machine learning to detect art forgery in paintings. Yuan-Sen's past endeavors include semi-professional gaming, where he was once recognized as a top Night-Elf player in Warcraft 3 in Malaysia.
The Grand Challenge Questions of Solar Wind Physics
Dr Nicholeen Viall (Research Astrophysicist at NASA/GSFC)
The solar atmosphere is heated to millions of Kelvin, which is several orders of magnitude hotter than the visible solar surface below. This hot atmosphere is a plasma, and flows outwards, forming a super Alfvénic solar wind that defines the heliosphere. The solar wind is comprised of structures across a range of scales, with complexity among the structures due to a competition between those structures that are imposed and injected directly from the solar atmosphere, and dynamical evolution as the solar wind flows outwards. There have been remote observations of the solar corona for centuries, and in situ measurements of the solar wind for almost 60 years. Computer simulation capabilities have commenced, and simulation techniques of the cross-scale and cross-regional coupling continue to advance. Yet there are longstanding, major unsolved pieces of this puzzle, involving universal physical processes such as magnetic reconnection, turbulence, and waves. In this talk, we discuss these grand challenge questions and discuss progress and future prospects with recent result from Parker Solar Probe, and Solar Orbiter, as well as the expected results from the upcoming Polarimeter to Unify the Corona and Heliosphere mission.
Dr. Nicholeen Viall is a Research Astrophysicist at NASA’s Goddard Space Flight Center, with expertise in solar coronal and solar wind physics. She is a winner of the 2018 NASA Early Career Achievement Medal, and was the 2018 recipient of the Karen Harvey Prize, awarded by the Solar Physics Division of the American Astronomical Society (SPD/AAS). She currently serves as the SPD/AAS vice Chair and is the Mission Scientist for NASA’s Polarimeter to UNify the Corona and Heliosphere (PUNCH) mission.