Date of Award

2019

First Advisor

Michael Bergman

Second Advisor

Eric Kramer

Abstract

Supermassive black holes (SMBHs) are known to situate at mas- sive galactic centers, which frequently merge to form more massive galaxies. It follows that SMBH binaries (SMBHBs) are expected to be common in our universe. SMBHBs at close separation are defined as binaries with sub-parsec separation. Sub-parsec SMBHBs emit strong gravitational waves (GWs), making them important for the study of gravitational wave backgrounds of compact object, although there is no confirmed compact SMBHB from observation. Massive black hole binaries with large separations, on kilo-parsec (kpc) scale, have been resolved in x-ray, optical and infrared. How- ever, compact SMBHBs are still challenging to image. A series of sky surveys, including Palomar Transient Factory and Catalina Real- time Transient Survey, have been used to search for compact SMBHB candidates. Others searched for indirect signatures to identify their binary nature, such as the periodic modulation from hydrodynamic simulations and relativistic Doppler boost. This thesis will review the techniques used to identify binaries and test the Doppler boost signature of a well-known compact SMBHB candidate, PG1302-102 (hereafter PG1302). My research advisors Zoltan Haiman, Maria Charisi and I used these techniques to identify PG1302 as a binary candidate. We constructed a rigorous statistical approach to test the null hypothesis that Doppler boost and intrinsic quasar variability (or damped random walk, DRW) is the cause of periodic variability of PG1302. I wrote a program in Python for the above statistical anal- ysis that will be explained in details in the data analysis section.

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