10/15 (Tues): Zhiyuan Ji, Patrick Kamieneski

LGRT 533

Tuesday 10/15 is on a Monday Schedule
Open to graduate students

Zhiyuan Ji:

Title: Hubble tension between the Early and the Late Universe

Abstract: Predictions made by the Lambda-CDM paradigm has been extensively shown to be consistent with many aspects of modern observational cosmology. The corresponding basic cosmological parameters are being measured with unprecedented precision. Discrepancies between observations in the Early and the Late Universe, however, seem to be confirmed with high significance, which might indicates the requirement of an expansion of the standard cosmological model. In my talk, I will review the different observational technologies of measuring the Hubble constant, both in the Early and the Late Universe, including potential systematics behind different measures. I will also briefly describe the ongoing/near future efforts that astronomers and physics are trying to make to ‘’solve’’ this tension.

Patrick Kamieneski:

Title: The effect of galaxy mergers on star formation rates from z=0-4 The effect of galaxy mergers on star formation rates from z=0-4

Abstract: Galaxy mergers and interactions play a crucial role in our current conception of galaxy evolution and hierarchical structure in the Universe. In the case of some of the most extreme objects yet observed, including Ultra-luminous Infrared Galaxies (ULIRGs) and Dusty Star-forming Galaxies (DSFGs), mergers are often assumed to be at least partially responsible for elevated star formation rates. However, it has been difficult to quantify by how much merger activity typically amplifies star formation. Studying the statistical effect of galaxy mergers on the build-up of stellar mass is fundamental to understanding the growth and evolution of galaxies across cosmic time. In addressing this question, I will present recent results from Pearson et al. 2019, including the use of convolutional neural networks to identify mergers in the SDSS, KiDS, and CANDELS surveys, spanning a redshift range of 0 to 4.