Title: A Multi-Waveband Overview of the Circumgalactic Medium and Dark Baryons on Cosmic Scales Speaker: Dr. Benjamin Oppenheimer (UAM/University of Colorado Boulder) Date: 2026-05-05 • 04:00 PM - 05:00 PM Location: Sala 300 (M8)

Abstract: I will introduce a general overview of the non-luminous, “dark” baryons in our Universe from the perspective of observational facilities operating in different wavebands. My research centers on using simulations and analytical methods to model the essential astrophysics and overall distribution of these baryons around galaxies, the so-called Circumgalactic Medium, as well as in the large-scale Cosmic Web, the Intergalactic Medium. I will lead us on a tour of measuring and comprehending dark baryons by discussing five observational methods: 1) Ultraviolet absorption, 2) X-ray emission, 3) the Sunyaev-Zel’dovich Effect measured against the Cosmic Microwave Background, 4) Fast Radio Bursts, and 5) molecular emission measured by JWST. I will attempt to unify these disparate wavebands under the theme of galactic-scale feedback originating from both stellar-driven and black hole-driven outflows that redistribute baryons relative to dark matter. I hope to finish by discussing future multi-waveband synergies for on-going and upcoming research projects.

Read more: https://weiguangcui.github.io/DECAF/blog#2026-05-05