Logan Fries
Astrophysicist
About Me
I am currently a Kavli Fellow at the Kavli Institute for Astronomy & Astrophysics located at Peking University in Beijing, China. My work focuses, broadly, on supermassive black hole growth and evolution over the history of the Universe. I received my Ph.D. in Physics at the University of Connecticut in May 2025, where my thesis focused on the two fundamental parameters governing black holes: their mass, and spin. These two parameters ultimately tell us the growth history of black holes over cosmic time. Mass tells us how much the black hole has eaten over its lifetime, while spin tells us how the black hole has eaten its mass. Understanding these two parameters is crucial for understanding the growth and evolution of black holes, and how they interact with their host galaxies.
Outside of astrophysics, I love to play basketball, tennis, and soccer! I am an avid sports fan, and coming from Kansas City, Missouri, I am a huge Chiefs and Royals fan! I also love to play guitar and sing, read classic and contemporary literature, cook, and take 35mm photography! Some of my favorite film photos are shown below!
Resume
Download CVExperience
Kavli Institute for Astronomy & Astrophysics
Postdoctoral Research Fellow
September 2025 - Present
Education
University of Connecticut
Doctorate of Philosophy in Physics
Dissertation: Echo Mapping the Kinematic Environments of Supermassive Black Holes
Ph.D. Advisor: Jonathan Trump (no relation)
August 2019 - May 2025
My Ph.D. dissertation focused on the kinematic environments around supermassive black holes at the centers of galaxies. In particular, understanding the effect of non-virial kinematics on the estimation of black hole masses outside of the local Universe, and understanding how to constrain the spin distribution of black holes over the past ten billion years.
University of Missouri - Kansas City
B.Sc. in Physics
August 2015 - December 2018
Graduated cum laude with a minor in mathematics, and philosophy.
Recent Publications
Recent Publications.
The SDSS-V Black Hole Mapper Reverberation Mapping Project: Light Echoes of the Coronal Line Region in a Luminous Quasar (ApJ, submitted)
Smith, Fries, Trump, et al.
New Insights into Quasar Dynamics This study is the first to investigate the light echoes from the coronal line region in a luminous quasar, providing new insights into the geometry and dynamics of the broad-line region as well as placing constraints on the radius of the coronal-line region.
The SDSS-V Black Hole Mapper Reverberation Mapping Project: A Kinematically Variable Broad-line Region and Consequences for the Masses of Luminous Quasars
Fries, Trump, Horne, et al. 2024
Black hole masses under fire! This study investigates the kinematic properties of the broad-line region in a luminous quasar, with implications for black hole mass estimates. It is revealed that the virial product, which should remain constant for a given mass, is non-constant throughout the ten year monitoring period.
The SDSS-V Black Hole Mapper Reverberation Mapping Project: Multi-Line Dynamical Modeling of a Highly Variable Active Galactic Nucleus with Decade-long Light Curves
Stone, Shen, Anderson, et al. incl. Fries 2024
Dynamical Modeling Reveals Complex BLR Dynamics. We present dynamical modeling of the quasar, RM160, studied in Fries et al. 2023, 2024. We find that there is strong evidence for non-virial motions in the broad-line region as suggested in both Fries+23,24. As suggested in Fries+24, we also find that the data reveal complex, time-evoling, and potentially transient dynamics of the broad-line region gas.
The SDSS-V Black Hole Mapper Reverberation Mapping Project: CIV Broad Absorption Line Acceleration in the Quasar SBS 1408+544
Wheatley, Grier, Hall, et al. incl. Fries 2024
Carbon IV Broad Absorption Acceleration. We present results of the CIV Broad Absorption Line (BAL) variability in the quasar SBS 1408+544, observed over nearly a decade-long monitoring campaign. The CIV BAL shows significant variability, with changes to the velocity indicating an acceleration over time. We present these results in the context of BAL acceleration models.
Exploring Changing-look Active Galactic Nuclei with the Sloan Digital Sky Survey V: First Year Results
Zeltyn, Trakhtenbrot, Eracleous, et al. incl. Fries 2024
Weak Accretion Yields Changing Looks. We investigate 116 quasars where, at least, one broad-emission line has disappeared throughout the monitoring period. We find that the changing-look events are preferentially at lower Eddington ratio systems.
The Sloan Digital Sky Survey Reverberation Mapping Project: Investigation of Continuum Lag Dependence on Broad-line Contamination and Quasar Properties
Sharp, Homayouni, Trump, et al. incl. Fries 2024
Accretion Disks: More Complex than Previously Thought! We investigate the relationship between accretion disk size and quasar properties from a sample of 95 SDSS quasars. We find an anti-correlation between continnum lag and luminosity, suggesting an accretion disk model featuring magnetic coupling between the disk and corona.
The SDSS-V Black Hole Mapper Reverberation Mapping Project: Unusual Broad-line Variability in a Luminous Quasar
Fries, Trump, Davis, et al. 2023
Potential Electromagnetic Signature of a Supermassive Black Hole Binary? This study investigates the unusual broad-emission line profile variability of a luminous quasar. The results suggest complex broad-line region kinematics, with potential implications for black hole mass estimates.
A Transient "Changing-look" Active Galactic Nucleus Resolved on Month Timescales from First-year Sloan Digital Sky Survey V Data
Zeltyn, Trakhtenbrot, Eracleous, et al. incl. Fries 2022
Record Breaking Changing Look Quasar! We present one of the quickest changing look quasar transitions known to date within a month timescale. We interpret the changing look transition as a variable line-of-sight obscuration, which faces several theoretical challenges.
Studying the physical properties of tidal features - I. Extracting morphological substructure in CANDELS observations and VELA simulations
Mantha, McIntosh, Ciaschi, et al. incl. Fries 2019
A Novel Way to Identify and Quantify Tidal Features. This study presents a new method for identifying and quantifying tidal features in galaxy mergers. The approach combines observational data with simulations to provide insights into the dynamics of tidal interactions.
