When:
Tuesday, April 22, 2025
11:00 AM - 12:00 PM CT
Where: 1800 Sherman Avenue, 7-600, Evanston, IL 60201 map it
Contact:
CIERA Astrophysics
(847) 491-8646
Group: CIERA - CIERA Colloquia
Category: Lectures & Meetings
Description:
One of the longstanding questions in galaxy dynamics is what determines whether a rotating stellar disk remains stable or forms a bar. While local stability criteria—like the Toomre Q parameter—have provided valuable insights, a general global criterion for bar formation has remained elusive. In this talk, I will present results from a new suite of high-resolution N-body simulations designed to test the global stability of stellar disks to the m = 2 bar mode. Crucially, our models do not assume that the disk is isolated and purely self-gravitating. Instead, the disk evolves within an external gravitational field, reflecting more realistic galactic environments. Our analysis identifies two key global, dimensionless parameters that appear to govern the onset of bar instability. These two parameters define a "stability plane" that separates bar-stable from bar-unstable systems. Unlike local criteria, this new framework provides a physically motivated, global condition for bar formation that can be applied across a wide range of galactic environments—including gas-rich, turbulent disks at high redshift. I’ll discuss the implications of this result for understanding the emergence of bars across cosmic time and in galaxies like our own Milky Way.
Speaker: Elena D'Onghia, Associate Professor, University of Wisconsin, Madison
Host: Tjitske Starkenburg
CIERA Colloquium: Chris Conselice: "The First Galaxies and Early Galaxy Formation with JWST"
When:
Tuesday, April 29, 2025
11:00 AM - 12:00 PM CT
Where: 1800 Sherman Avenue, 7-600, Evanston, IL 60201 map it
Contact:
CIERA Astrophysics
(847) 491-8646
Group: CIERA - CIERA Colloquia
Category: Lectures & Meetings
Description:
I will present the recent discovery of a significant number of the most distant galaxies and AGN in the universe (6.5 < z < 18) using the JWST Prime Extragalactic Areas for Reionization and Lensing Science (PEARLS) GTO survey, as well as public JWST data. This is currently one of the largest JWST investigations of its kind to date, with over 100 square arcmins spanning six fields. I will present the details of our z>6.5 sample of more than 1000 galaxies, including many new candidates between 14<z<20, increasing by a significant amount the number of galaxies at this epoch. My talk will describe how our reliable sample at the highest redshifts is identified, present their structure, star formation and stellar population properties, as well as their merger rates and new results on AGN in early galaxies. I will conclude with the implications of our results for the theoretical ideas behind galaxy formation as well as what our results imply about the reionization of the universe.
Speaker: Chris Conselice, Professor, University of Manchaster, United Kingdom
Host: Fred Rasio
CIERA Colloquium: Malena Rice: "Insights from the Orbital Architectures of Planetary Systems"
When:
Tuesday, May 6, 2025
11:00 AM - 12:00 PM CT
Where: 1800 Sherman Avenue, 7-600, Evanston, IL 60201 map it
Contact:
CIERA Astrophysics
(847) 491-8646
Group: CIERA - CIERA Colloquia
Category: Lectures & Meetings
Description:
The current configurations of planetary systems each provide a snapshot in time, encoding fossilized clues about the prevalence and diversity of systems’ evolutionary pathways. Orbital architectures, therefore, offer fundamental insights into the physical processes shaping planetary systems at both the individual and population level. In this talk, I will describe recent advances in our understanding of the 3D orbital architectures of planetary systems, outlining both observational constraints and their theoretical implications. I will discuss how the dynamic relationship between stars and planets informs the underlying processes sculpting diverse planetary systems.
Speaker: Malena Rice, Assistant Professor, Yale University
Host: Jason Wang
When:
Tuesday, May 13, 2025
11:00 AM - 12:00 PM CT
Where: 1800 Sherman Avenue, 7-600, Evanston, IL 60201 map it
Contact:
CIERA Astrophysics
(847) 491-8646
Group: CIERA - CIERA Colloquia
Category: Lectures & Meetings
Description:
TBA
Speaker: Nick Winters, Assistant Professor of Classics, Northwestern University
Host: Lena Murchikova
When:
Tuesday, May 20, 2025
11:00 AM - 12:00 PM CT
Where: 1800 Sherman Avenue, 7-600, Evanston, IL 60201 map it
Contact:
CIERA Astrophysics
(847) 491-8646
Group: CIERA - CIERA Colloquia
Category: Lectures & Meetings
Description:
TBA
Speaker: Jared Males, Associate Astronomer, University of Arizona
Host: Jason Wang