I'm a postdoctoral fellow working with Dr. Marcin Sawicki. My main areas of interest are galaxy evolution, galaxy assembly, stellar populations, spatially resolved stellar populations, and spectral analysis.
Grism Data
I work with JWST/NIRISS grism data, mainly from the CANUCS survey.
Forward Modelling
To deal with the systematics of grism data I use a forward modeling technique.
Stellar Populations
I derive metallicities, ages, and other stellar population parameters.
Formation Histories
I constrain (non-parametric) star-formation histories for massive quiescent and star-forming galaxies.
Science
CLEAR. I. Ages and Metallicities of Quiescent Galaxies at 1.0 < z < 1.8 Derived from Deep Hubble Space Telescope Grism Data
Using a forward modeling technique, we fit the stellar populations of a sample of 31 massive quiescent galaxies in the CLEAR survey, in a redshift range of 1 < z < 1.8. Our measurements indicate that massive quiescent galaxies in this redshift range have ~ solar stellar metallicities. Thus, there is no evolution in the stellar metallicity - mass relation, up to a redshift of z ~ 1.8. We also show that many of these galaxies had formed ~70% of their stellar mass by z ~ 2-3.
CLEAR II: Evidence for Early Formation of the Most Compact Quiescent Galaxies at High Redshift
Combining photometric, G102 grism, and G141 grism data, we constrain the stellar populations and derive "non-parametric" star-formation histories for a sample of 97 massive quiescent galaxies in the CLEAR survey, in a redshift range of 0.8 < z < 2.5. By comparing formation redshifts (where the galaxy formed half its mass) to stellar surface mass densities within 1 kiloparsec we see that the most compact galaxies are biased to form early (z>2.5), while less compact galaxies show a wide range of formation redshifts. Our results favor a scenario where compact galaxies formed rapidly at high redshift, then go through subsequent evolution through minor mergers.
Outreach
I enjoy speaking with the public and have given several talks at Astronomy on Tap BCS.
I work with undergraduate students at Texas A&M. These research projects include creating an interactive website for the CLEAR collaboration, color gradients of quiescent galaxies, H-alpha maps of interacting galaxies, simulated JWST NIRCAM Paschen-alpha map for CEERS.
Contact
Address
Department of Physics and Astronomy
Mist 314
Texas A&M University, College Station, TX, 77843
vestrada78840@gmail.com