Phase-space dynamics
Galaxy redshifts define a projected radius-velocity space. The fastest galaxies trace the energy scale needed to escape the cluster potential.
Welcome.
Cosmology, Galaxy Clusters, Dynamics
I am Alex Rodriguez, a 6th-year astronomy PhD student at the University of Michigan and a Caltech/IPAC Visiting Research Fellow studying galaxy cluster dynamics, weak lensing, and the expansion history of the Universe.
Research Overview
From dynamics to cosmology.
Weak lensing and structure
Galaxy shear maps projected mass. I use weak lensing to study cluster substructure and identify candidate cosmic-web filaments.
Cosmological acceleration
Escape from a cluster depends on mass and on the accelerated expansion of the background universe.
Phase-Space Dynamics
The fastest cluster galaxies measure the potential.
The escape edge is the outer boundary of the radius-velocity diagram. More massive clusters have deeper potentials, so their fastest galaxies reach higher velocities. Sparse sampling lowers the measured edge.
Measured edge
82% of true profile
AS1063
Escape Velocity Mass of AS1063
A disturbed massive cluster where the escape-velocity mass agrees with lensing and SZ estimates.
Rodriguez et al. 2024
Cluster Sample
Weak Lensing and Escape-Velocity Concordance
A larger cluster sample showing strong agreement between independent lensing and escape-velocity mass estimates.
Rodriguez & Miller 2025
Velocity Dispersions
Galaxy Velocity Bias in Galaxy Cluster Observations
We measure \(\sigma_v\) for 45 clusters in observations and measure the predicted velocity bias to be at the same level as relative differences in cosmological simulations.
Rodriguez et al. 2026a (in prep)
Cosmology
A dynamical probe of dark energy.
The escape velocity profile is affected by the expansion of the background, making it the only known dynamical probe of cosmology, complementary to distance-based probes.
This is particularly attractive when analyzing the expansion history of our universe through probes like \(q(z)\), where recent DESI results have hinted at decelerating cosmologies. Rodriguez 2026b, in prep.
Measured edge
82% of true profile
Lensing and Dynamics
Projection, redshifts, and orbital structure.
My lensing and earlier dynamics work ask how gravitational systems assemble, from galactic nuclei to cluster-scale filaments.
MACSJ0600
Mapping a cosmic-web node
Subaru/HSC shear shows projected mass structure around MACS J0600.1-2008. Magellan/IMACS spectroscopy will test whether those features are genuine cluster-connected filaments.
Rodriguez et al. 2026c (in prep)
Nuclear Dynamics
Eccentric nuclear disks
Eccentric nuclear disks with a secondary SMBH can induce slowed secular evolution, along with eccentricity oscillations, aligning the disk and enhancing TDE rates.
Rodriguez, Generozov & Madigan 2021Teaching and Outreach
Astronomy for classrooms, museums, and the public.
Science Communication Fellowship
Scientist Spotlight
Designed a hands-on demo for children explaining how galaxies can escape from galaxy clusters.
Planetarium
Museum of Natural History
Served for two years as a planetarium presenter, designing and giving interactive astronomy shows for the public.
Lead Instructor
ASTRO 127: Naked Eye Astronomy
Led four semesters and eight mini-terms as part of the Michigan Graduate Teaching Cerificate (GTC) requirements, designing lectures, labs, assignments, and projects on the Sun, Moon, planets, stars, comets, meteors, and the motion of the sky.
Quantitative Finance
Astronomy methods for financial markets.
I interned at Wells Fargo in Summer 2025 as a Quantitative Analyst in Market and Counterparty Risk Analytics, where I modeled correlated default structure in global portfolios using unsupervised learning and multi-factor regressions. I am interested in alpha research at the intersection of Bayesian inference, variational methods, entropy-based modeling, and unsupervised learning. My astrophysics research has trained me to extract weak signals from noisy, incomplete, high-dimensional data, and I am excited to apply that background to latent market structure, systematic trading signals, and market prediction.