2026-09-23T20:39:55Z https://www.ideals.illinois.edu/oai-pmh

oai:www.ideals.illinois.edu:2142/121390 2023-12-13 col_2142_5131 col_2142_14807 com_2142_5130 com_2142_14806 com_2142_8903

Liu, Xin Gammie, Charles F Shen, Yue French, Decker K 2023-08 application/pdf en text Submission original under an indefinite embargo labeled 'Open Access'. The submission was exported from vireo on 2023-12-04 without embargo terms The student, Yu-Ching Chen, accepted the attached license on 2023-05-23 at 22:41. The student, Yu-Ching Chen, submitted this Dissertation for approval on 2023-05-23 at 23:07. This Dissertation was approved for publication on 2023-05-30 at 09:50. DSpace SAF Submission Ingestion Package generated from Vireo submission #18888 on 2023-12-04 at 16:59:34 Searching for binary and dual supermassive black holes in large surveys Chen, Yu-Ching 2023-05-30 Active Galaxies Quasars Binaries, Galaxy Evolution Surveys 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. No gravitational wave has yet been detected from the coalescence of a binary SMBH in the local universe. Evolution of binary SMBHs from kilo-parsec to sub-parsec scales and their interactions with host galaxies are still not well understood. Active SMBHs, known as quasars, provide an excellent way to study distant SMBHs in electromagnetic waves. A census of dual and binary quasars in different scales remains an essential puzzle in many aspects of astronomy. This dissertation consists of several studies aimed at searching for dual and binary quasars on different scales, from kiloparsec to milli-parsec. Chapter 2 focuses on discovering kilo-parsec dual quasar candidates using a novel astrometric technique. Chapter 3 presents a case study of a confirmed kiloparsec dual quasar in a galaxy merger at a redshift of 2.17. In Chapter 4, the focus shifts to the search for dual/offset quasar candidates with parsec-scale separations. Chapter 5 presents a systematic search of periodic quasars, which are thought to be sub-parsec binary SMBHs, using optical light curves. Chapter 6 investigates the precessing jet scenario for three periodic quasar candidates discovered in Chapter 5. This thesis paves the way for discovering dual and binary quasars using various methods and provides implications for future telescopes and surveys. Text eng https://hdl.handle.net/2142/121390 Copyright 2023 Yu-Ching (Tony) Chen Ph.D. Dissertation Astronomy University of Illinois at Urbana-Champaign Astronomy