Detectability of Self-Lensing Supermassive Black Hole Binaries in Quasars
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Authors
Dancewicz Helmers, John
Issue Date
2022
Volume
Issue
Type
Thesis
Language
en_US
Keywords
Alternative Title
Abstract
Active galactic nuclei (AGN) or quasars are distant and luminous objects thought to be powered accretion into supermassive black holes (SMBHs) whose luminosity rivals that of their local galaxy. Since most galaxies are thought to contain SMBHs and galaxies commonly merge, it is likely that some AGN contain two SMBHs. While a few dual-AGN or supermassive black hole binaries (SMBHB) have been discovered at parsec (pc) and kiloparsec separations, there are currently no unambiguous detection of SMBHBs (Tremblay et al. 2016; Bansal et al. 2017)[1][2]. One promising new detection technique is through gravitational self-lensing events which may be possible with upcoming observing programs. This thesis develops a method to predict the probability that a given SMBHB system will generate a detectable lensing event by varying the geometric parameters defined by gravitational lensing geometry. The probability that a SMBHB is located at a given separation is calculated by comparing timescales of the different phases of the SMBHB’s lifespan with its total lifespan. This is then combined with the lensing probability to create a probability distribution of lensing events at different separations and masses. This paper explores the effects of different parameters on the probability distribution, focusing primarily on the mass of the SMBHB, its separation distance, the inclination of the system, and the mass ratio of the two black holes. The detectable lensing events from each parameter combination are then combined to determine the overall rate of detectable lensing events that could be detected in a given population. A method is developed to predict lensing characteristics of corresponding magnification and orbital period for different system conditions. Combining the observables with the probability function allows the number of lensing events that are likely to be detected by the upcoming Vera C. Rubin observatory to be determined. Based on this study, the Rubin observatory, will detect up to ∼ 1.9 × 104 lensing events over a 10-year period. This methodology can be adapted to the specification of other datasets and is hereby presented to the quasar research community.
Description
2022
Citation
Publisher
Creighton University
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