| Tuesday, October 8, 2024 |
| Machine Learning Chalk Talk | |
| David Hogg et. al | |
| Event Type: Special Seminar | |
| Time: 11:00 AM - 12:15 PM | |
| Location: 726 Broadway, 940, CCPP Seminar | |
| Abstract: MLCT is a weekly seminar hosted by the Physics department where anyone—students, postdocs, faculty—can present a 45-minute-ish lecture or discussion on machine learning or statistical inference. The setting is informal, chalkboard-focused (with optional slides), and interruptions are encouraged. Topics can range from rough ideas to finished research, with the assumption that the audience is at the level of a graduate student who has some knowledge of how typical ML methods work. To see a weekly schedule of seminars, see https://dwh.gg/MLCT For those wondering, What is the Style of the Talk? A useful talk should be research-level-oriented, with a strong emphasis on explicit mathematical explanations and interpretations of machine learning methods. The focus should be on methodological insights rather than just presenting results, with a particular interest in understanding why methods succeed or fail. If there are tutorials, they should go beyond basic introductions, offering deeper, pedagogical insights. | |
| JWST's Little Red Dots: Masters of Disguise in the High-Redshift Universe | |
| Fabio Pacucci, Center for Astronomy, Harvard University | |
| Event Type: Astro Seminar | |
| Time: 2:00 PM - 3:00 PM | |
| Location: 726 Broadway, 940, CCPP Seminar | |
| Abstract: This talk will explore the exciting journey to probe several populations of black holes, spanning from the distant to the local Universe. I will focus primarily on the "little red dots" (LRDs), a newly discovered and puzzling population of compact red sources at redshift z > 4, identified by JWST. These objects challenge our current astrophysical models in several ways. First, I will discuss the detection of overmassive black holes relative to the stellar mass of their host galaxies. Second, I will address the X-ray weakness problem, where these sources remain undetected in deep X-ray surveys. I will use advanced GRRMHD simulations to show how mildly super-Eddington accretion onto slowly spinning black holes can resolve this issue. Third, I will explore the extremely high stellar densities at the cores of these objects and their potential for triggering runaway stellar collisions. Throughout the talk, I will also discuss how the LRDs represent a perfect bridge to study other populations of black holes, with a focus on the role of future and perspective observatories such as HWO and AXIS. These include the search for black hole seeds at redshifts z = 20-30 and the detection of quiescent black holes in the local Universe. | |