2022-12-21 Abstract
Title: Searching for kpc dual quasars at cosmic noon
Speaker: Yu-Ching (Tony) Chen
Date: December 21 at 13:00
Location: R521, General Building II
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 seems inevitable, direct observational evidence of binary SMBHs has been elusive. Luckily, at the cosmic noon (z~2), the number density of active SMBHs---known as quasars---and the star formation rate peaked, providing an excellent large quasar sample to search for binaries. I will introduce our recent efforts of finding small-scale dual quasars. We used the Gaia survey and Hubble Space Telescope to uncover dual quasars at sub-arcsecond scales (corresponding to < 8kpc at z=1). With Gaia’s high angular resolution and astrometric accuracy, we also discovered Gaia-unresolved dual quasars using a new astrometric technique. The follow-up multi-wavelength observations confirmed the natures of several dual quasars. Those kpc dual quasars are excellent samples to yield constraints on many cosmological simulations and study the triggering of quasar activity due to galaxy mergers. I will summarize the talk with future plans and challenges.