Other Astrophysics and Astronomy Commons^™

Considering Numerical Relativity For Upgrades In Mcfacts Merger Dynamics, Shawn K. Ray

Dissertations, Theses, and Capstone Projects

Binary black hole mergers (BBH), some likely originating from active galactic nuclei (AGN), are observed by ground-based detectors such as LIGO-Virgo-KAGRA (LVK) and will be detected by future space-based detectors such as the Laser Interferometer Space Antenna (LISA) and the Laser Interferometer Lunar Antenna (LILA). The dynamics of AGN may be responsible for a significant fraction of BBH mergers soon to be observed by LISA and LILA, yet the dynamics of BBH mergers within AGN disks remains ambiguous despite their appearance in gravitational wave observations. Monte carlo For AGN Channel Testing and Simulation (McFACTS) is an open-source software used to …

Probing The 'Mev Gap': Discovery And Characterization Of Persistent And Transient Mev-Gev Gamma-Ray Sources With The Fermi Large Area Telescoope, Scott Joffre

All Dissertations

The MeV Gap is a moniker for the energy regime E~0.1-100 MeV that has lacked sensitive observations for the last 20 years. This is not out of scientific disinterest, but observational challenges. The only instrument currently available to make observations in the MeV Gap is the Fermi Large Area Telescope (LAT). For the first time ever, Fermi-LAT has been leveraged to push its observational capabilities to its absolute lower energy limit to end this 20-year observational gap. Observing the MeV sky is imperative for identifying some of the most luminous galaxies in the Universe known as blazars. The brightest blazars …

From Bobcat To Bursts: Multi-Messenger Constraints On Supermassive Black Holes And Binaries, Jessica Sydnor

Graduate Theses, Dissertations, and Problem Reports (ETD)

Supermassive black hole binaries (SMBHBs) are a natural consequence of hierarchical galaxy formation and evolution. When galaxies merge, their central supermassive black holes (SMBHs) are expected to form bound pairs that evolve from kiloparsec to sub-parsec separations under the influence of dynamical friction, stellar scattering, and gas dynamics. Ultimately, these SMBHs reach the regime where gravitational wave emission dominates and drives the final inspiral and coalescence. Understanding the formation, evolution, and observational signatures of SMBHBs is critical to advancing multi-messenger astrophysics, particularly in the era of pulsar timing arrays (PTAs) and the upcoming Laser Interferometer Space Antenna (LISA), which opens …

Comparison Between Galfit And Lenstronomy To Analyze The Host Galaxies Of Reverberation Mapped Active Galactic Nuclei, Samantha Kay Allen

Physics

Active Galactic Nuclei (AGN) are some of the brightest objects within our Universe. Most galaxies contain a supermassive black hole (SMBH) at their center, but not all are powered by active accretion which can form an AGN. Due to the conservation of angular momentum, dust and gas rotate around the SMBH to form a disk. The large gravitational potential energy from the SMBH is converted into heat through friction, which produces a hot and luminous source of light. As a result, the SMBH is unresolved. Through a technique known as reverberation mapping (RM), the mass of the SMBH has been …

Differential Photometry Of Active Galactic Nuclei Using Time Resolved Observations With The 1m Nickel Telescope Of Lick Observatory, Chance L. Spencer

Physics

Active galactic nuclei (AGNs) are exotic objects in the center of some galaxies with luminosities that can greatly outshine the stars of the host galaxy across the entire electromagnetic spectrum. The origin of the UV/optical light is thought to be due to accretion of material onto the supermassive black hole in their centers. Since these objects are too far away to resolve the gravitational sphere of influence of the black hole directly, we make use of a method called reverberation mapping. We measure the lag between the AGN power-law continuum emitted by the accretion disk and the Doppler-broadened emission lines …

Probing The Fitting Accuracy Of Active Galaxy Spectra, Aaron T. Line

Physics

Prior to this study, Dr. Vardha N. Bennert and collaborators selected a sample of ~100 local active galaxies to study the relationships between black hole mass and host galaxy properties. The broad Hβ width is necessary to determine black hole mass. This value is determined using a spectral decomposition code was scripted in IDL by Dr. Daeseong Park. The script fit spectral features and collected data for properties such as width of emission lines and continuum contribution percentages. The results were logged for further analysis.

To probe the accuracy of the fitting process, artificial spectra were created and fitted to …