Pratik Gandhi awarded Frontera Fellowship

The Texas Advanced Computing Center (TACC) selected Pratik Gandhi for a Frontera Computational Science Fellowship! This fellowship will provide one year of tuition and stipend, including a computing allocation on Frontera and collaboration and mentorship with members of TACC, for Pratik’s PhD project: Near-Far Connection: Using the Stellar Fossil Record of Local Group Dwarf Galaxies to Probe the Epoch of Reionization. Congratulations Pratik!


The National Science Foundation (NSF) has awarded me a Faculty Early Career Development Program (CAREER) grant of $800,117 for Galactic Archeology: Understanding the Building Blocks of the Milky Way across Cosmic Time.

This article from UC Davis College of Letters & Science highlights this award.

With this award, we seek to model and understand how our Milky Way and similar galaxies formed across cosmic time. We also develop a library of interactive Jupyter notebook tutorials, based on these simulations, to promote learning in computational analysis. Thank you to all current and former members of my group, as well as the FIRE collaboration, for helping to enable this science!

NASA Astrophysics Theory Program (ATP) grant: dark-matter subhalos and stellar streams

NASA’s Astrophysics Theory Program (ATP) has awarded our team (PI Robyn Sanderson, co-PI Andrew Wetzel) a grant for Predicting observable signatures for dynamical interactions between dark-matter substructure and stellar streams in the Milky WayCongratulations to Robyn Sanderson, who led this grant!

The wealth of ongoing and upcoming observations of the Milky Way promise an era of ‘near-field cosmology’ to test the cold dark matter (CDM) paradigm. One of the most exciting and powerful probes of dark matter is using the Milky Way’s stellar streams as ‘gravitational antennae’, as close passages of small dark-matter subhalos dynamically perturb cold stellar streams, allowing us to test the diverging predictions of different dark-matter models for the low-mass end of the (sub)halo mass function. Our goal with this grant is to use our Latte suite of FIRE-2 simulations of Milky Way-like galaxies to model the dynamics of dark-matter subhalo interactions with stellar streams from disrupted globular clusters and satellite galaxies in realistic detail, including creating synthetic observations of these simulated perturbed streams. Our goal is to provide the first comprehensive end-to-end study that connects cosmological predictions from baryonic simulations to interpretations of, and predictions for, observable perturbations from dark-matter subhalos on stellar streams.

Hubble Space Telescope (HST) Treasury Program: M31-6D survey

Space Telescope Science Institute has awarded our team

  • PI  Dan Weiz
  • co-PI  Nitya Kallivayalil
  • co-PI  Andrew Wetzel
  • co-investigators:  Jay Anderson, Gurtina Besla, Mike Boylan-Kolchin, Tom Brown, James Bullock, Andrew Cole, Michelle Collins, Mike Cooper, Alis Deason, Andrew Dolphin, Aaron Dotter, Mark Fardal, Annette Ferguson, Tobias Fritz, Marla Geha, Karoline Gilbert, Raja Guhathakurta, Rodrigo Ibata, Michael Irwin, Myoungwon Jeon, Evan Kirby, Geraint Lewis, Dougal Mackey, Steve Majewski, Nicholas Martin, Alan McConnachie, Ekta Patel, Mike Rich, Josh Simon, Evan Skillman, Tony Sohn, Erik Tollerud, Roeland van der Marel

a Hubble Space Telescope (HST) Treasury Program of 244 orbits for Tracing the 6-D Orbital and Formation History of the Complete M31 Satellite SystemThese Hubble Space Telescope (HST) observations will provide the initial baselines for long-term proper-motion measurements for all of the known satellite galaxies around Andromeda (M31). Our goal is to measure the orbital motions of these satellites as they move across the sky over the next ~10 years, to complete their full 6-dimensional orbital phase-space. Our key science goals are to:

  • Understand the effect of environment on low-mass galaxy evolution
  • Use low-mass galaxies as probes of the epoch of reionization
  • Dynamically measure the mass distribution of M31’s dark-matter halo
  • Test planar associations of satellite galaxies

Combined with our existing HST Treasury Program to measure proper motions for all of the satellite galaxies of the Milky Way, we will provide proper motions for all known satellite galaxies across the Local Group.

Hubble Space Telescope (HST) Legacy Theory grant: low-mass galaxies and reionization

Space Telescope Science Institute has awarded our team

a Hubble Space Telescope (HST) Legacy Theory grant for Probing the epoch of reionization with the fossil record of nearby dwarf galaxies. Our goal is to use our FIRE-2 simulations to rigorously test and characterize how well HST near-field observations of the star-formation histories of low-mass galaxies in the Local Group can measure the faint end of the galaxy ultra-violet luminosity function during the epoch of reionization at z ~ 7. Furthermore, we will create synthetic HST and JWST observations of these simulated galaxies, to quantify how accurately the SFHs from measured stellar populations in nearby low-mass galaxies can infer their star formation rates and UV luminosities at z ~ 7, and we will release these synthetic observations and simulation data to the scientific community, to help leverage existing HST data and guide upcoming JWST observations.

Hellman Fellowship


The Society of Hellman Fellows has selected me as a 2019 Hellman Fellow, for my research program: Using stars as gravitational antennae to measure dark matter. The Hellman Fellowship supports the research of assistant professors. This grant will help support the work of our group to use our Latte suite of FIRE-2 simulations to develop new dynamical models to measure the nature of dark matter, by using streams of stars as ‘gravitational antennae’ for interactions with dark-matter subhalos, thus translating dark-matter theories directly into measurable predictions for stellar dynamics.


Scialog Fellowship and Heising-Simons grant

The Research Corporation, with support of the Heising-Simons Foundation and the Kavli Foundation, once again has selected me to be a Scialog Fellow. I was delighted again to join 50 fellows at the 2019 Scialog conference on Time Domain Astrophysics in Tuscon, Arizona, during which we discussed exciting applications of data from NASA’s TESS space telescope, ESA’s Gaia space telescope, and the Zwicky Transient Facility.

I am excited that the Heising-Simons Foundation selected the grant that Keith Hawkins, Jennifer van Saders, and I submitted during this meeting: Aging Gracefully: Stellar Ages Across the HR Diagram and Their Implications for Galactic Archaeology. With this seed funding, our goal is two-fold:

  1. Use the Latte FIRE-2 Milky Way-like simulations as a testbed to quantify the observational precision in stellar ages that we require for specific Milky Way studies.
  2. Compile a unified framework for combining/comparing different ways of measuring stellar ages in an easy-to-use Baysian framework.

    I am excited to work with Keith and Jen on this project over the next year!

NASA Astrophysics Theory Program (ATP) grant: modeling the Milky Way

NASA’s Astrophysics Theory Program (ATP) has awarded our team

a grant for Modeling Galactic Archaeology of the Milky WayKudos in particular to Robyn Sanderson, who led a significant component of our science case. Our primary goal with this grant is to turn our Latte suite of FIRE-2 simulations of Milky Way-like galaxies into synthetic star catalogs and mock surveys of the Milky Way, and make these datasets publically available, to provide theoretical predictions and tools for the many surveys of the Milky Way, including the Gaia space telescope.