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Physics & Astronomy Colloquium – Spring 2019 – Werk

April 24, 2019 @ 3:30 pm - 5:00 pm

Speaker: Jessica Werk (University of Washington, Seattle)

Title: Why Circumgalactic Matter Matters for Galaxy Evolution

Abstract: The circumgalactic medium (CGM; non-ISM gas within a galaxy virial radius) regulates the gas flows that shape the assembly and evolution of galaxies. Owing to the vastly improved capabilities in space-based UV spectroscopy with the installation of HST/COS, observations and simulations of the CGM have emerged as the new frontier of galaxy evolution studies. In the last decade, we have learned that the CGM of Milky Way mass galaxies likely contains enough material to harbor most of the metals lost in galaxy winds and to sustain star-formation for billions of years. Remarkably, this implies that most of the heavy elements on earth cycled back and forth multiple times through the Milky Way’s own CGM before the formation of the solar system. In this talk, I will describe constraints we have placed on the origin and fate of this material by studying the gas kinematics, metallicity and ionization state. I will conclude by posing several unanswered questions about the CGM that will be addressed with future survey data and hydrodynamic simulations in a cosmological context.

Speaker Biography:

Jessica Werk studies the extended gaseous components of galaxies and the role they play in galaxy formation and evolution. She is primarily an observational astronomer with expertise in optical and ultraviolet spectroscopy, and uses both ground and space-based telescopes to carry out her research. She works closely with theorists in defining observational constraints for cosmological simulations (such as those generated in the UW N-body shop), and in physically interpreting her own observations.

Professor Werk’s current research focuses on the “invisible” ionized gas of galaxies in two largely unexplored regimes: (1) the dark-matter halo and (2) the disk-halo interface. Ultimately, she would like to understand the complex galactic ecosystems in which baryons cycle through many physical phases over hundreds of kiloparsecs, from the interiors of stars to the intergalactic medium.

Outside of astronomy, she enjoys strenuous hikes up tall mountains, duplicate bridge, and singing Puccini arias to her dog.


April 24, 2019
3:30 pm - 5:00 pm
Event Categories:


Gallalee Hall 227
United States


Karen Lynn