Astrophysics Brown Bag Lunch Talk 11/7/2022: Speakers: Aritra Ghosh (Yale University) And Yanlong Shi (Caltech)

In Person in Marlar and/or Virtual Brown Bag Lunch 
Monday November 7, 2022 at 12:00 Link Below
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Presentation in Marlar 37-252/37-272 for those wishing to attend in person

Aritra Ghosh, Yale at 12:05 (in person )

Estimating Galaxy Morphological Parameters for ~8 Million Galaxies in the Hyper Suprime-Cam Wide Survey using Bayesian Machine Learning

Abstract: In this talk, I will introduce GaMPEN — an ML framework that can predict full Bayesian posteriors for morphological parameters of galaxies – it produces 40% more accurate uncertainties at 1/100th of the run-time compared to light-profile fitting algorithms. Using GaMPEN, we have created one of the largest morphological catalogs currently available, containing ~8 million Hyper Suprime-Cam (HSC) galaxies with estimates of bulge-to-total light ratio, effective radius, flux, and their associated uncertainties. Currently, we are using this catalog to probe the relationship of morphology with the environment and the buildup of mass, shutting down star formation in these galaxies.

Bio: I am a final-year Ph.D. candidate at Yale University. I use the latest advances in machine learning combined with large surveys to study the formation & evolution of galaxies and investigate the specific role played by Active Galactic Nuclei in this process.


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Yanlong Shi, CalTech at 12:30 pm (remote)

Accretion and feedback of seed BHs in giant molecular clouds

Abstract: I will introduce our recent progress in simulations of BH accretion and feedback in star-forming giant molecular clouds, especially the possibility of hyper-Eddington accretion. In the first part, I will talk about the condition without BH feedback, which is the necessary condition for hyper-Eddington accretion. The second half will contain the simulation with radiative-inefficient feedback models for BH and a parameter survey of BH feedback, including radiation, jets, and cosmic ray.

Bio: Yanlong is a 5th-year graduate student at Caltech working on BH accretion/feedback, he is also highly interested in cosmology with large-scale structures.



Event Contact

Josh Borrow