The Spectral Energy Distributions of Active Galactic Nuclei with Direct Black Hole Mass Measurements
Author ORCID Identifier
https://orcid.org/0000-0003-0792-863X
Date of Award
8-9-2022
Degree Type
Dissertation
Degree Name
Doctor of Philosophy (PhD)
Department
Physics and Astronomy
First Advisor
Misty Bentz
Second Advisor
D. Michael Crenshaw
Third Advisor
Edward M. Cackett
Fourth Advisor
Russel J. White
Fifth Advisor
Merida Batiste
Abstract
Active galactic nuclei (AGNs) are powered by accretion of material onto their central supermassive black holes and are unique in that they emit radiation across the entire electromagnetic spectrum. Spectral energy distributions (SEDs) allow for a comparison of the energy that is emitted in each wavelength regime. Our goal is to construct the most accurate multi-wavelength SEDs by reexamining the near-IR to X-ray SEDs of 23 AGNs with reverberation mapped (RM) black hole mass measurements. These SEDs will allow us to constrain measurements, such as bolometric luminosity and accretion rate and, in turn, these measurements can be used to better understand physical processes of AGNs and how they influence the host galaxy. To improve on previous studies, this set of SEDs consists of simultaneous optical/UV/X-ray data taken by XMM-Newton and is supplemented by ground-based near-IR data to constrain the red tail. Using two-dimensional decompositions of high-resolution Hubble Space Telescope images, combined with galaxy spectral templates, we constrain and remove the host galaxy contribution and focus the SEDs on the accretion powered AGN flux. We also consider the impacts of internal reddening and the effects of broad and narrow line region emission. Finally, given the highly variable nature of AGNs, we examine 4 objects from this sample with 200-300 simultaneous optical/UV/X-ray Neil Gehrels Swift Observatory observations and quantify how variability impacts the shape of the SEDs and the scatter in measurements of bolometric luminosity and accretion rate.
DOI
https://doi.org/10.57709/29366502
Recommended Citation
Merritt, Rachael, "The Spectral Energy Distributions of Active Galactic Nuclei with Direct Black Hole Mass Measurements." Dissertation, Georgia State University, 2022.
doi: https://doi.org/10.57709/29366502
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