Bryce Wedig

About Me

I’m a PhD candidate in physics at Washington University in St. Louis. I work with Professor Tansu Daylan on observational cosmology. I'm interested in what galaxy-galaxy strong gravitational lenses can tell us about the nature of dark matter.

I completed an MPhil in History and Philosophy of Science and Medicine at the University of Cambridge where I specialized in the philosophy of physics. Before Cambridge, I completed a BA at Kenyon College with a double major in physics and philosophy. I also spent a year as a visiting student at the University of Oxford studying physics and philosophy of physics.

Here are my CV, GitHub profile, ORCID, and LinkedIn.

Publications

The Roman View of Strong Gravitational Lenses

Wedig et al. 2025, submitted

Images of galaxy-galaxy strong gravitational lenses can constrain dark matter models and the Lambda Cold Dark Matter cosmological paradigm on sub-galactic scales. Currently, there is a dearth of images of these rare systems with high signal-to-noise and angular resolution. The Nancy Grace Roman Space Telescope (hereafter, Roman), scheduled for launch in late 2026, will play a transformative role in strong lensing science with the planned wide-field surveys. With its remarkable 0.281 square degree field of view and diffraction-limited angular resolution of 0.11 arcsec, Roman is uniquely suited to characterizing dark matter substructure from a robust population of strong lenses. We present a yield simulation of detectable strong lenses in Roman's planned High Latitude Wide Area Survey (HLWAS). We simulate a population of galaxy-galaxy strong lenses across cosmic time with Cold Dark Matter subhalo populations, select those detectable in the HLWAS, and generate simulated images accounting for realistic Wide Field Instrument detector effects. We predict around 93,000 detectable strong lenses in the HLWAS, of which about 500 will have sufficient signal-to-noise to be amenable to detailed substructure characterization. We investigate the effect of the variation of the point-spread function across Roman's field of view on detecting the suppression of the subhalo mass function at low masses and individual subhalos. Our simulation products are available to support strong lens science with Roman, such as training neural networks and validating dark matter substructure analysis pipelines.

Software

mejiro

mejiro ("meh-JI-roe") is a pipeline to simulate space telescope images of galaxy-galaxy strong gravitational lenses built on SLSim, lenstronomy, pyHalo, and GalSim. "mejiro" (メジロ in Japanese) or "warbling white-eye" (Zosterops japonicus) is a small bird native to East Asia with a distinctive white ring around the eye, much like the shape of a strong lens.

GitHub Documentation