About Me

Education: The Pennsylvania State University: University Park, BS in Astrophysics with a minor in Philosophy

Research Interests: Observational Astronomy, Computational Astrophysics, High Energy Astrophysics

Research

Seeding Supermassive Blackholes: The formation of supermassive black holes (SMBHs) is a key open problem in galaxy evolution, with5 light- and heavy-seeding models predicting distinct black hole occupation fractions (BHOFs). Using6 multiwavelength observations from the LSST Deep Drilling Fields, we measure the AGN fraction and7 estimate the BHOF across 0 < z < 1. Applying a hierarchical Bayesian model, we find that the8 inferred BHOF remains 100% for host galaxy masses below 10^9M⊙ at lower redshifts. These findings9 are consistent with light-seed scenarios. Additionally, we computed the black hole masses for several10 galaxies in the W-CDF-S to test the mass-weighted black hole occupation distributions from semi-11 analytic models (SAM). Using a reduced-χ2 analysis, we find that the data are consistent with the12 main-sequence accretion model regardless of the assumed seeding mechanism. These results provide13 new observational constraints on SMBH seeding and highlight the value of combining deep extragalactic14 surveys with probabilistic modeling.

Publications:

Gianni Sims, Vicki Sarajedini (October 2026), Constraining Supermassive Black Hole Seeding and Accretion via Occupation Fractions and Mass-Weighted Distributions, Submitted to The Astrophysical Journal. [arXiv:2610.35673]

Kallan Berglund, Martin Bojowald, Manuel Diaz, and Gianni Sims (January 2024), Quasiclassical Solutions for Static Quantum Black Holes, Physical Review D [PDF]

Media and Public Engagement: Sims, G. (2025). Featured in Black Space Week: Black In Astro community feature. Nature Astronomy. https://doi.org/10.1038/s41550-025-02581-z (June 2025)

Photo Creds: NASA’s Goddard Space Flight Center/Jeremy Schnittman, 2020

Community

Teaching: General Physics Lab 2048L, General Physics Lab 2049L, General Physics Lecture 2048

Outreach:

Student Council Member of the National Society of Black Physicists (NSBP): Role includes co-founding and co-leading NSBP's first mentorship program named Uplift Physicists Program.

Undergraduate Research Showcase: Judge I assisted judging undergraduate students presenting their research during the Black in Astro Space Week (June 2023)

Equity & Inclusion: Onaketa Tutor I am currently a mid-level online math and physics tutor as well as a mentor to underrepresented students ranging from middle school to high school.

Exhibitor: I represented the National Society of Black Physicists Organization at the STEMNoire Conference in June of 2025.

Contact

Email: gsims2021@fau.edu

Address: 777 Glades Road, Boca Raton, FL, 33431