Searching for binary and dual supermassive black holes in large surveys

Chen, Yu-Ching

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https://hdl.handle.net/2142/121390 Copy

Description

Title

Searching for binary and dual supermassive black holes in large surveys

Author(s)

Chen, Yu-Ching

Issue Date

2023-05-30

Director of Research (if dissertation) or Advisor (if thesis)

Liu, Xin

Doctoral Committee Chair(s)

Gammie, Charles F

Committee Member(s)

• Shen, Yue
• French, Decker K

Department of Study

Astronomy

Discipline

Astronomy

Degree Granting Institution

University of Illinois at Urbana-Champaign

Degree Name

Ph.D.

Degree Level

Dissertation

Keyword(s)

• Active galaxies
• Quasars
• Binaries, Galaxy evolution
• 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 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.

Graduation Semester

2023-08

Type of Resource

Thesis

Copyright and License Information

Copyright 2023 Yu-Ching (Tony) Chen

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