Galactic Archaeology

Orbital Torus Imaging

A fundamental goal of physics & astronomy is to understand the nature of dark matter because it is the main driver of structure in the Universe. This is why a significant amount of effort is spent developing, implementing, and testing the tools astronomers use to constrain the mass of Local Group Galaxies. Traditional methods assume a simplistic form for the gravitational potential and a time-invariant distribution function. Additionally, they only make use of kinematic observations of tracers in these systems. We recently understand that a steady-state distribution function does not describe our galaxy since we can now detect perturbations to the Milky Way and have gained an appreciation for the disequilibria in our galactic disk.

My research will implement and extend Adrian Price-Whelan's dynamical inference method Orbital Torus Imaging, which leverages kinematics and chemical abundances to more precisely and more accurately constrain the dark matter distribution in our Galaxy and other stellar systems, in the Feedback in Realistic Environments (FIRE) simulations. As my advisor, Prof. Sarah Loebman, is a PI in this collaboration I have access to several Milky Way-like galaxies and the expertise of noted simulators and dynamicists. It is fascinating to me that we are at this pivotal moment in history since for the first time we are able to make use of the vast wealth of information that is available to us to discover exciting truths about our Universe!

I was ecstatic presenting my research at the 240th Annual Meeting of the American Astronomical Society in Pasadena!

Galactic Phylogeny

Our goal is to understand galactic evolution. In order to do this, we can use the concept of heritability, the inheritance of traits (for stars, the trait we care about is their chemical abundance). Evolutionary trees from biology allow us to visualize the change that occurs between generations of stars. My work is inspired by Prof. Paula Jofre, who has used phylogenetic trees to identify different families of stars (old, intermediate-age, and young) for Megan Bedell's sample of solar analogs. This is a different way of figuring out how stars are related since it clusters them in chemistry space and provides a reduction in dimensionality by calculating the pairwise chemical distance of stars (Paula has compared up to 55 elements, I have access to 11) and uses that single metric to assign stars their place on the tree. In this way, we can reconstruct the formation history of a galaxy and constrain our models of galaxy evolution. With the help of my advisor, Prof. Sarah Loebman, I have generated the first phylogenetic tree for simulated stars and was able to recover a similar self-sorting into age groups based on chemical information alone. I intend to plant (visualize) more trees hopefully in 3D so we can "climb" the tree, explore stellar relationships, and gain a deeper appreciation about the overall structure of different FIRE simulated galaxies!

Presentation slides:

Other Research

Observational astronomy REU at University of Wyoming:

Additionally, I spent a beautiful summer in Laramie, Wyoming doing research with my REU advisor, Prof. Michael Brotherton. I learned how to plan a night of observation using the WIRO 2.3 m telescope on Mt. Jelm. It was very hands-on as we obtained optical spectroscopy of targets in our survey overnight and then during the day reduced and analyzed our data. This work produced densely sampled light curves for the continuum and Hβ emission lines of many quasars. Our goal was to characterize the masses of supermassive black hole binary systems using a technique called reverberation mapping. My contribution led to this publication!

Condensed matter experimental research at CSULB:

As an undergraduate eager to jump into research, I began working in Prof. Chuhee Kwon's lab at Cal State Long Beach. I learned how to analyze samples of nanosphere monolayers treated with 100 Å-thick permalloy films using contact mode atomic force microscopy and lateral force microscopy (AFM/LFM) and tapping mode (TM) on the atomic force microscope. In order to assess the magnetic properties of the self-assembled hexagonal close-packed ordering formed by individual nanospheres, I used tip contact to the sample to generate a digitally-rendered image of our samples. This research had applications in biophysics, for example, use of magnetic nanospheres as drug delivery systems and a method to destroy cancer cells.

Climbing the WIRO 2.3 m telescope! Many of my happiest nights were spent here.

Prof. Danny Dale took the 2019 REU cohort bouldering. I miss Wyoming's natural beauty very much - breathtaking!

Presenting my research on supermassive black hole binary systems at my first AAS meeting!

Prof. Chuhee Kwon's experimental group. Thanks for giving me the confidence to pursue research!


Applied Galactic Dynamics Summer School:

I am super grateful that I got to participate in the Big Apple Dynamics School where I worked with my mentors David Hogg, Adrian Price-Whelan, Emily Cunningham, and Tjitske Starkenburg on implementing and comparing several different methods used to constrain the galactic gravitational potential. I generated simple dynamical systems to which I applied Jeans modeling, Schwarzschild modeling, and Orbital Torus Imaging in order to recover the known potential parameters of my system. Here, I was introduced to and fascinated by the minutiae of what goes into being a practicing astronomical data analyst: Bayesian statistical inference, covariance matrices, maximum likelihood estimation, and the nuances of fitting a line to data among many other things. This experience led me to become further enthusiastic about how I can leverage newly-available observables to decode the history of the Milky Way and better understand galactic formation and evolution. Thanks to everyone at the Flatiron Institute!

Lick Observatory Observational Astronomy Workshop:

Another really cool experience was participating in this observational astronomy workshop at Lick Observatory. I grew an appreciation for all the considerations that observers make when planning a night at the telescope (what calibrations you may need to perform, calculating approximate exposure times, which targets are available on a given night, etc.). I learned about and even got to use some of the many telescopes that are a resource for UC students such as myself: the Shane 3-m telescope, the Nickel 1-m reflector, and the 0.6 m CAT). I loved learning about the historical significance of the observatory. Seeing original notebooks documenting events like the naked-eye discovery of Jupiter in the archives while Paul, ever the raconteur, perfectly captured the awe was completely mind-blowing to me.  

4th of July with my Galactic Dynamics Summer School cohort!

I had so much fun learning about the history of Lick Observatory & using the telescopes! Thank you, Paul, Ellie, Jon, and all the staff at UCO/Lick who made this possible.

I had the opportunity to meet other UC astro grads here. I made lots of friends!