Colloquium: Dr. Yu-Ching (Tony) Chen | JHU
In-Person PHYS 401
Wednesday, February 25, 2026 · 11 AM - 12 PM
TITLE: "Cosmic Duets: Finding and understanding active supermassive black hole pairs at cosmic noon”
ABSTRACT: The observed structure of the universe suggests that galaxy mergers and the co-evolution of their central supermassive black holes (SMBHs) are common throughout the cosmos. While the formation of binary SMBHs is theoretically inevitable, direct observational evidence remains elusive. The evolution of binary SMBHs from kiloparsec to subparsec and their interactions with host galaxies are still poorly understood. However, quasars, which are active SMBHs, offer a powerful way to trace these processes across the electromagnetic spectrum. In this talk, I will present our results from a multi-scale search for dual and binary quasars. Our search, spanning scales from kiloparsecs to milliparsecs, leverages diverse data from time-domain and wide-field surveys—including Gaia, Dark Energy Survey (DES), and Sloan Digital Sky Survey (SDSS)—to identify and characterize these systems. I will also present new results from dedicated James Webb Space Telescope (JWST) observations investigating the host galaxy properties of kpc-scale dual quasars. I will conclude by summarizing our key results and their implications for the search for binary and dual quasars in ongoing and future telescopes and surveys.
ABSTRACT: The observed structure of the universe suggests that galaxy mergers and the co-evolution of their central supermassive black holes (SMBHs) are common throughout the cosmos. While the formation of binary SMBHs is theoretically inevitable, direct observational evidence remains elusive. The evolution of binary SMBHs from kiloparsec to subparsec and their interactions with host galaxies are still poorly understood. However, quasars, which are active SMBHs, offer a powerful way to trace these processes across the electromagnetic spectrum. In this talk, I will present our results from a multi-scale search for dual and binary quasars. Our search, spanning scales from kiloparsecs to milliparsecs, leverages diverse data from time-domain and wide-field surveys—including Gaia, Dark Energy Survey (DES), and Sloan Digital Sky Survey (SDSS)—to identify and characterize these systems. I will also present new results from dedicated James Webb Space Telescope (JWST) observations investigating the host galaxy properties of kpc-scale dual quasars. I will conclude by summarizing our key results and their implications for the search for binary and dual quasars in ongoing and future telescopes and surveys.
