10/11/2024
By Amanda Vozzo
Physics Colloquium, Wednesday, Oct. 16, 2024 at 4 p.m. in Ball 214
Speaker: Silas Laycock, Associate Professor at UML will give a talk on “Seeing Double - Astrophysics with Binary Stars.”
Abstract: Binary stars range from solar systems with twin Suns to the most extreme environments in the universe: accreting black holes and neutron stars. Astronomers use binaries to study fundamental physics: measuring star's exact masses, behavior of matter in strong magnetic and gravitational fields, gravitational lensing, gravitational waves. Binaries can also exhibit tidal interaction and accretion, with both effects modifying stellar evolution. This talk will follow the story of the X-ray binary known as IC 10 X-1, a heavyweight pairing of a massive star and a black hole that could represent the upper mass limit for stellar black holes. Such binaries are logically precursors of double-degenerate systems (e.g. BH+BH and NS+BH). These in turn are the parent population of the merger events that generate gravitational waves, such as those detected by LIGO. Stellar black holes are also implicated as seeds from which the supermassive BHs in the cores of galaxies first grew.
As a case-study in how massive stellar BHs can get, the tale of IC 10 X-1 is fraught with unexpected twists. Different interactions between the black hole and the star have come to light, pushing astronomers to use tools ranging from X-ray timing with Chandra, to UV spectroscopy with Hubble. In the near future, infrared observations with JWST will test a hypothesis about how the black hole's high-energy radiation modifies the star's stellar wind. At stake is the validity of BH mass determination in some of the (apparently) highest-mass systems.
Bio: Silas Laycock received his BS and MS, with honors, in Physics and Astronomy, from the University of Southampton, UK in 1999. He received his Ph.D. in Astrophysics from the University of Southampton in 2003. He joined UMass Lowell in Fall 2010, following postdoctoral research at Gemini Observatory and Harvard Smithsonian Center for Astrophysics. His research interests include Pulsars, Black Holes, Binary Stars, X-rays, High Energy Radiation, Optical Spectroscopy and Adaptive Optics. He was also responsible for the setting up and opening of Schueller Observatory on South Campus at UML. He has also been instrumental in shaping the teaching of introductory courses at UML, introducing various pedagogical innovations targeted towards improving student outcomes.