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.

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