About
I am a graduate student in the Department of Physics at New York University, advised by Jeremy Tinker. My research focuses on the galaxy-halo connection, although my interests extend beyond galaxy formation into cosmology and physics beyond the standard model.
I originally studied Computer Science at Worester Polytechnic Institute (2011), going on to work at Microsoft as a software engineer for seven years. While in Seattle, I had the privledge to work with and learn from many great engineers. I worked both on large established software systems and on scrappy incubation projects over my time there. I returned to academia to pursue my passion for physics, initially studying at the University of Washington before joining NYU for my PhD.
Research Interests
The Galaxy-Halo Connection
Galaxies are born and live their lives in dark matter halos. Using data from the Dark Energy Spectroscopic Instrument (DESI), I build galaxy group catalogs to understand how galaxies occupy halos. This creates important datasets for studying how the dark matter environment affects galaxy formation and evolution. My first DESI catalog will be available here. In the meantime, older catalogs from my advisor are here.
The Circumgalactic Medium
Galaxies are surrounded by dilute gas in their halos that is difficult to detect and study. My collaborators and I demonstrated that using Fast Radio Bursts (FRBs) as probes, it will be possible to measure the gas profiles around galaxies. These measurements will have big implications for our understanding of galaxy formation and evolution.
Nature of Dark Matter
The particle nature of dark matter remains one of the biggest mysteries in physics. Different dark matter models predict different small-scale structure in the universe, leading to many opportunities to constrain and identify the nature of dark matter. My early work at UW helped explored whether axion dark matter substructures might survive and be detectable.
Publications
My publications can also be viewed on NASA ADS.
- Ian Williams, Jeremy Tinker, et al. "Galaxy Groups from the DESI DR1 Bright Galaxy Survey." In preparation.
- Ian Williams, Adnan Khan, and Matthew McQuinn. "Baryonic post-processing of N-body simulations, with application to fast radio bursts." Monthly Notices of the Royal Astronomical Society, Volume 520, Issue 3, pp. 3626-3640 [arXiv] [DOI]
- Huangyu Xiao, Ian Williams, and Matthew McQuinn. "Simulations of axion minihalos." Physical Review D, Volume 104, Issue 2, article id. 023515 [arXiv] [DOI]
Teaching & Mentoring
Teaching Experience
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Guest Lecturer, Quarks to Cosmos, NYU
(Spring 2026)
Lectures on neutron stars and relativity for a general undergraduate audience.
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Guest Lecturer, Astronomy 100, Hunter College
(Fall 2025)
Lectures on cosmology for a general undergraduate audience.
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Teaching Assistant, General Physics 1, NYU
(Fall 2023)
Ran a lab section for a mechanics class for pre-med students.
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Instructor, internalDrive Tech Camps
(Summer 2008)
Ran courses on video game development and programming for middle and high school students.
Mentoring
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Aatmaj Nagarkar, Tanish Parida: high school students
(2025 - Present)
Project: comparing optical group catalogs to eROSITA X-ray cluster catalogs.
- Michael Badgett: Microsoft Software Engineer (2017 - 2018)
Contact
Email: ianwilliams@nyu.edu
Office: Room 945, 726 Broadway
Department of Physics
New York University
New York, NY 10003