Colloquia Schedule

Thiago Goncalves
Thursday, February 16, 2023
3:45 p.m.
LGRT 1033
Title:
Lyman break analogues: local laboratories for galaxy formation and evolution under extreme conditions
Abstract:
The universe experienced the peak of star formation activity approximately 10 billion years ago, but objects at such epochs are difficult to observe in detail due to the large distances involved. In this talk, I will discuss the background and recent results of a series of works on a sample of local analogues of high-redshift star forming galaxies. These objects, selected based on their high UV luminosities and surface brightness, show characteristics more akin to galaxies at z ~ 1.5-2, while their proximity allows for detailed investigations of a wide variety of physical properties, including (among others) kinematics, gas masses, and environments. They also show signs of nuclear accretion onto central intermediate mass black holes, and as such could act as interesting laboratories for an important brief stage of black hole growth before the M-sigma relation is fully established.
Johanna Vos
Thursday, February 23, 2023
3:45 p.m.
LGRT 1033
Title:
To Be Determined:
Nicole Arulanantham
Thursday, March 2, 2023
3:45 p.m.
LGRT 1033
Title:
UV-driven Evolution and Chemistry of Protoplanetary Disks: Insights from HST’s ULLYSES Program
Abstract:
Beginning in December 2019, approximately 70 T Tauri stars were observed at UV wavelengths through the Hubble UV Legacy Library of Young Stars as Essential Standards Director's Discretionary program (ULLYSES). These publicly available spectra provide critical observational constraints on UV irradiation of protoplanetary disks, a key driver of the gas phase chemistry that sets the initial conditions for planet formation. We use the HST data and radiative transfer models to reproduce the LyA emission seen by surface layers of the gas disks, which typically makes up the largest component of the total integrated UV flux. The model LyA flux available to photodissociate molecules like H2O, HCN, and CH3CN within disks with dust cavities and gaps varies by two orders of magnitude, and we explore how the spread might translate to observable chemical differences. We also investigate whether ultraviolet emission lines from UV-fluorescent H2 can be used to break the degeneracy between disk flaring and UV irradiation of the gas in models of sub-mm CN emission. This work is critical for interpreting molecular features in T Tauri systems observed with ALMA and JWST, demonstrating how UV radiation propagates from the accretion shocks to the outer disks.
To Be Determined
Thursday, March 9, 2023
3:45 p.m.
LGRT 1033
Title:
To Be Determined:
John Weaver
Thursday, March 30, 2023
3:45 p.m.
LGRT 1033
Rachel Bezanson
Thursday, April 6, 2023
3:45 p.m.
LGRT 1033
Grant Wilson
Thursday, April 13, 2023
3:45 p.m.
LGRT 1033
Title:
LMT Project
Laurent Pueyo
Thursday, April 20, 2023
3:45 p.m.
LGRT 1033
Title:
To Be Determined:
Erin Kara
Thursday, April 27, 2023
3:45 p.m.
LGRT 1033
Chris Hayward
Thursday, May 4, 2023
3:45 p.m.
LGRT 1033
Joe Burchett
Thursday, May 11, 2023
3:45 p.m.
LGRT 1033