My research is primarly focused on developing accretion theory, but I am interested in all areas of black hole astrophysics. Using large numerical models, I work to understand the dynamics of the gas in accretion disks. The ultimate goal is to characterize the accretion physics well enough to connect fundamental accretion theory to observables, so that the distinct signatures found in variability studies can be properly interpreted.
I also use multiwavelength observations of active galactic nuclei (AGNs) to understand the diversity of supermassive black hole environments. Through this work I have used a number of ground-based telescopes, like the 3.5-meter ARC telescope at the Apache Point Observatory and the 4.3-meter Discovery Channel Telescope, as well as space-based telescopes, like the Hubble Space Telescope and the Chandra X-ray Observatory.
Thanks to my thesis advisor Dr. Chris Reynolds and a constant stream of strong coffee, I have made several contributions, detailed below. Outside of the office, I enjoy riding bikes and can be found at road and mountain bike races across the southeast and mid-Atlantic during the summer. I'm also an avid reader and recreational chess player.
X-ray follow-up of two unusually red AGNs from the Swift Burst Alert Telescope (BAT) All-Sky Survey. We show that the AGNs are heavily obscured and possible analogs of extremely red objects (EROs), an elusive class of objects typically found at higher redshift.
Timing studies find that the variability from accreting black holes displays organized, nonlinear structure on viscous timescales. This is interpreted as evidence of the multiplicative combination of stochastic fluctuations in the mass accretion rate, though the model is largely phenomenological. Using a numerical model of an MHD accretion disk, I showed for the first time that these characteristic signatures naturally develop from MHD turbulence and that the magnetic dynamo drives their development.
Accretion disks with an inner truncation are invoked to explain the spectral properties of certain classes of black hole systems. The truncation is attributed to a transition in the radiative efficiency of the gas. Here, I study a hydrodynamic accretion disk with a bistable cooling law, meant to emulate such a transition. Several interesting features develop, which are distinct from the canonical model used to explain observations. This work establishes a benchmark against which an MHD model can be compared.
Here I continue the investigation into the behavior of a truncated accretion disk, but modeled in MHD. The dynamics, angular momentum transport, and energetics of the accretion flow are studied and reveal a gentle outflow originates from a "truncation zone." This leads to a subtle, but important, interaction between the hot gas and the cold Keplerian disk.
In addition to these publications, I have another paper that has been submitted to the Astrophysical Journal. Throughout my accretion theory work, the role of the magnetic dynamo has been forefront in influencing the global disk evolution. To better understand the magnetic dyanmo and the large-scale magnetic field behavior, I also explored the dependence of the dynamo cycle on accretion disk thickness. Please contact me if you would like a copy of the submitted draft, and I will gladly share it.
Currently, the bulk of my research focus is on the observational investigation of a candidate recoiling AGN. Using multi-band, high-resolution Hubble imaging, Chandra X-ray observation, and multi-epoch optical spectroscopic monitoring, I will determine if this AGN is indeed a recoiling AGN. Please check back for future updates!