Astrophysics & Planetary Sciences Colloquia

The Emergence of Galactic Structure

Using a combination of the Hubble Space Telescope, the Keck telescopes, and the ALMA millimeter interferometer, we have begun to piece together a picture of the emergence of galactic structure: how the Universe evolved from its uniform state shortly after the Big Bang to the rich diversity of galaxies today. In this talk, I will discuss some of the results that have come out of my work and the impact they have had on our understanding of the formation and evolution of galaxies.

Simulating Galaxy Formation in the Early Universe

As techniques have improved over the last decade, observations have peered deep into the Universe’s history and begun to glimpse galaxies which formed in the first few billion years after the Big Bang. Evidence is mounting that galaxies in the early Universe appear and behave very differently from those nearby - for example, the most massive galaxies are extremely compact, and star-forming disks appear to have strange clumpy morphologies.

From Stellar Dynamics to Compact Binaries: Unlocking the Future of Gravitational Waves

Since the first detection over three years ago, gravitational waves have promised to revolutionize our understanding of compact objects, binary evolution, general relativity, and cosmology. But to make that a reality, we need to understand how and where these relativistic binaries form. In this talk, I will describe the various astrophysical pathways for creating the binary mergers detected by LIGO/Virgo, and how specific features of the gravitational waves (such as the binary eccentricities and black hole spins) can shed light on the formation of these dark remnants.

The Microphysics of AGN Feedback

Feedback from active galactic nuclei (AGN) is one of the most important processes governing the formation and evolution of galaxies and galaxy clusters. It is believed to be responsible for inhibiting the formation of massive galaxies and for solving the long-standing "cooling-flow problem" in galaxy clusters. A lot of understanding of AGN feedback has been gained using hydrodynamic simulations; however, some of the relevant physical processes are unresolvable or not captured by pure hydrodynamics, such as plasma effects and cosmic-ray (CR) physics.

Cosmic Extremes: Time-Domain Astrophysics in a Multi-Messenger World

Time-domain astrophysics provides a unique opportunity to study the most extreme physical processes in the Universe, including the deaths of massive stars, the destruction and creation of compact objects like neutron stars and black holes, and the tidal disruption of stars by supermassive black holes (SMBHs). With the pioneering detections of gravitational waves, astronomers and physicists have gained a new, complementary tool to study these cataclysmic events, with implications for fields as wide-ranging as general relativity, nuclear physics, cosmology, and shock physics.