Postdoc Colloquium - 4 short talks

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Postdoc Colloquium - 4 short talks

Tuesday, September 20, 2022, 03:30pm - 04:30pm

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Lauren Biddle, The University of Texas at Austin
Observing the Planet–Disk–Star Connection

Abstract

A major question in exoplanet science is the pathway for planetary formation and evolution. One approach to this problem is to infer the histories of planets by comparing the demographics of late-age planetary systems to those of young systems. However, in contrast to the wealth of exoplanet discoveries at late ages, there are significantly fewer confirmed planets at early ages (<10 Myr), and even fewer detected at close-in orbits around Classical T Tauri Stars (CTTS). A leading reason for this is largely a result of strong magnetic activity in CTTS observed in the form of long-lived cold spots and accretion hot spots, which can mimic planetary signatures and/or drown them out entirely. Using CI Tau as an example, I present an assessment of the photometric variability of stellar accretion over a range of timescales and its role in teasing out observational signatures of a hot-Jupiter orbiting near the inner edge of the disk.

Nika Jurlin, The University of Texas at Austin
Timing the Cycle of Life and Death of Radio Galaxies

Jed McKinney, The University of Texas at Austin
Heating and Cooling in Dusty Galaxies

Abstract

Star-formation depends on the physical conditions of the interstellar medium (ISM), where gas cooling, heating, and feedback from stars and supermassive black holes all compete to drive the evolution of galaxies. My research focuses on characterizing the cold gas from which stars form to better understand the origin of high star-formation rates in luminous, infrared (IR) galaxies today and in the past. I use combined spectroscopy from ALMA, the VLA, and Spitzer to measure physical quantities of interstellar gas and dust at z=0 and z~2. Compact, IR-luminous galaxies at all redshifts exhibit low gas heating efficiencies and high star-formation efficiencies, suggesting a link between the parsec-scale ISM properties of star-forming regions and the global evolution of the galaxy. There is tentative evidence for systematically low gas heating rates at z~2 which may contribute to the high star-formation rates and star-formation efficiencies at early times. I will briefly present ongoing projects and upcoming programs to statistically test this link between the efficiency of star-formation and gas conditions, and discuss how JWST can be used to push diagnostics of the ISM out to higher redshifts

Joseph Zalesky, The University of Texas at Austin
Understanding the Atmospheres of Substellar Worlds

Location: PMA 15.216B and online