2021
KICP Seminar: Yun-Ting Cheng (Caltech)
12:00–1:00 pm Zoom Room
Yun-Ting Cheng, Caltech, “Cosmology and Astrophysics with Intensity Mapping”
A&A Colloquium: Claude-André Faucher-Giguere (Northwestern)
3:30–4:30 pm Zoom - for link, please contact, Laticia
“How do galaxies form? New insights from FIRE and into the role of the circumgalactic medium”
Abstract: Galaxies are remarkably diverse in their properties, ranging from irregular to disky to elliptical in morphology, and from blue to red in color. At the same time, when analyzed systematically, galaxy populations exhibit striking regularities, with clear trends with mass and redshift. How does this “regular complexity” emerge from the hot Big Bang? I will present results from the FIRE simulations which shed some light onto the processes that shape galaxies. The FIRE zoom-in simulations resolve the multiphase interstellar medium of galaxies and model several different feedback processes (including Type II/Ia supernovae, stellar winds, and radiation) while including the cosmological environment. I will highlight recent results on the formation of disk galaxies, the “burstiness” of star formation, and galactic winds. Our new results indicate that transitions in each of these important phenomena can be simultaneously explained by a phase transition in the inner circumgalactic medium, “inner CGM virialization” (ICV), and arise from the interplay between feedback energy produced on small scales and the physics of halo gas on larger scales.
A&A Colloquium: Eve Ostriker (Princeton)
3:30–4:30 pm Zoom - for link, please contact, Laticia
“Star Formation and “feedback” in Giant Molecular Clouds”
Giant molecular clouds (GMCs) are the home of the most extreme conditions and the most dramatic events found in the interstellar medium (ISM). GMCs host the densest, coldest portion of the ISM’s gas, with gravitational collapse occurring in filaments and leading to the formation of star clusters. These young star clusters, in turn, host massive and luminous stars that profoundly alter — and ultimately destroy — their birth clouds, by an array of feedback processes. Historically, the effect of these ``feedback’’ processes was seen as optical emission nebulae centuries before — in the 1600s! — direct observations of molecular gas that makes up the majority of a cloud’s mass. In addition to the UV radiation that ionizes gas and creates highly-photogenic nebulae, non-ionizing UV also is important in applying radiation forces to dust. Stellar winds from massive stars are also present, but X-ray evidence of their impact its less apparent than expected, a longstanding puzzle. These feedback processes all contribute in shaping the evolution of GMCs, and it is believed that star formation is finally truncated by feedback-induced dispersal of gas, thereby setting the lifetime star formation efficiency. Within GMCs, turbulence plays several important and counteracting roles, including reducing star formation rates by dispersing dense regions, increasing porosity so that destructive radiation escapes, and mixing hot and cool gas at the fractal interface surrounding hot wind bubbles.
Given the complex array of processes involved, numerical simulations are essential to developing quantitative models of the lives and deaths of star-forming GMCs, and provide a laboratory for us to investigate the detailed physics of feedback. In this talk, I will describe results from recent radiation (magneto-) hydrodynamic simulations and theoretical models that have helped us to understand how star-forming GMCs self-regulate and guide the evolution of galaxies.
Tuesday Lunch Seminar: Yiming Zhong (UChicago) and Mike Zevin (UChicago)
12:00–1:00 pm Zoom
Yiming Zhong will tell us how to seed the first supermassive black holes from
self-interacting dark matter.
Mike Zevin will discuss our current understanding of the various
evolutionary pathways for forming binary black holes, and how
gravitational-wave observations have begun to constrain the relative
efficiencies of these channels as well uncertain physical processes
inherent to massive-star evolution.
Particle Physics Seminar: David Cinabro (Wayne State University/DOE)
3:30–4:30 pm Zoom Room
David Cinabro, Wayne State University/DOE, “Status of Belle II”
2020
Autumn Quarter Ends
All day
Open group seminar: Minghao Guo (Peking University)
4:00–5:00 pm Zoom Room
Minghao Guo, Peking University, “Hunting for Wandering Massive Black Holes”
Postdoc jamboree
2:00–4:00 pm Zoom Room
Join us for the traditional “Postdoc Jamboree” on 12/09 from 2:30pm-4:30pm and 12/11 from 2pm-4pm.
This will be a perfect opportunity to get to know our amazing group of postdocs, a bit about their science and hobbies.
Open Group Seminar: Nandita Khetan (Gran Sasso Science Institute)
1:30–2:30 pm Zoom room
Nandita Khetan, Gran Sasso Science Institute, “A new measurement of the Hubble constant using Type Ia supernovae calibrated with surface brightness fluctuations”
KICP Seminar: Christina Gao (Fermilab)
12:00–1:00 pm Zoom room
Christina Gao, Fermilab, “Axion Searches with two Superconducting Radio Frequency Cavities”