About me

I am a 4th year Ph.D. candidate at the University of California, Davis, working with Prof. Andrew Wetzel and Prof. Maruša Bradač. My primary research focuses on using cosmological zoom-in simulations with the FIRE collaboration to understand galaxy formation and evolution, particularly in the context of low-mass galaxies in the Local Group, although I dabble in some high-redshift galaxy observational work as well.

I was born and brought up in Mumbai, India, and moved to the United States in 2014 for my undergraduate studies at Yale University, before moving to Davis, CA in 2018 for graduate school.

Star Trek is a big part of my life, with my favourite series being DS9. My other hobbies include cooking, reading, cycling, and woodworking.

Research

Near-far connection: using the Local Group to Probe the Epoch of Reionisation

Gandhi, P. J., et al., (in prep)
Directly observing the faintest galaxies during the Epoch of Reionisation is extremely challenging, and may very well be beyond the capabilities of even JWST. In recent years, a "near-far approach" has gained interest, which aims at using the stellar fossil record of low-mass galaxies in the Local Group to infer the faint-end global UV luminosity function at z > 6. However, some major questions remain regarding the near-far approach, especially regarding the accuracy of reconstructing the star formation history of LG galaxies and whether the present-day low-mass galaxies in the LG are representative of the global galaxy population at z > 6.

I am using the FIRE cosmological zoom-in simulations combined with synthetic observation techniques to characterise, stress-test, and validate/invalidate the near-far approach and inform upcoming JWST observations of LG galaxies.


Metallicity-dependent rates of Type Ia supernovae

Gandhi, P. J., et al., (2022)
In Gandhi+22, I explored the need for metallicity-dependent rates of Type Ia supernovae and their impact on different aspects of galaxy formation. This work was motivated by results from large-scale supernova surveys (e.g. Brown et al., 2019; Wiseman et al., 2021; etc) showing that lower-mass galaxies have higher specific Ia rates than higher-mass ones, and independently by observations showing that the close-binary fraction of solar-type stars in the Milky Way is anti-correlated with metallicity (e.g. Moe, Kratter, & Badenes 2019).

Using the FIRE cosmological zoom-in simulations, I demonstrated that there exist a range of metallicity-dependent Ia rate models that bridge the discrepancy between theoretical and observed rates, and that some of those models also lead to improved agreement in galaxy abundances (like the stellar mass-metallicity relation) without significantly affected other galaxy properties overall (e.g. stellar masses, morphologies, etc).


Strong & weak gravitational lens modelling of Hubble Frontier Fields clusters

NASA/ESA/STScI
On the high-redshift observation side of things, I am producing gravitational lens models of the HFF cluster Abell S1063. For this, I am using the SWUnited code that combines strong and weak lensing constraints (Bradač et al., 2005).

Obtaining accurate lens models, convergence maps, and magnification maps is crucial for understanding our observations of background high-z galaxies lensed by such clusters, and serves to further our understanding of the galaxy populations and conditions during the Epoch of Reionisation.





List of Publications

ADS library of my 1st- and nth-author papers

Outreach & Science Communication

  • Astrobites

    I am a writer and DEI committee co-chair for astrobites, a graduate-student run astronomy blog sponsored by the AAS. We write daily easily digestible summaries of recent astronomy papers, interviews with astronomers, as well as guides on different topics like applying to graduate school, how to write papers, coding, etc. Visit our website to learn more!

  • Astronomy on Tap, Davis

    I co-organise the regular Davis chapter of the global Astronomy on Tap science cafe network, where we host exciting, accessible public talks on all things astronomy. They're open to everyone and held at Sudwerk Brewing Co. in Davis. Follow us on facebook or twitter to hear about upcoming events, and email us at astronomyontapdavis[at]gmail[dot]com to sign up for our mailing list!

Teaching

  • Upper-division Astrophysics: PHY 153 -- Galaxies and Extragalactic Astrophysics
  • Lower-division Astrophysics: AST 25L -- Astronomy Lab for majors
  • Non-major Course: AST 10G -- Introduction to Astronomy (Galaxies & Cosmology)
  • Physics Lab Course: PHY 7B -- second quarter of intro physics for life science majors
  • Physics Lab Course: PHY 7A -- first quarter of intro physics for life science majors