Astrophysics Research

This page provides a brief description of the various research projects I have been fortunate to be apart of. Below outlines my current projects at MSU and my past undergraduate projects with a link to the culminated paper.

Current Research Projects at MSU

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3D Morphology of the Magellanic Clouds using red clump stars

I use red clump (RC) stars as precise distance indicators to map the three-dimensional structure of the Magellanic Clouds. These stars provide a powerful way to trace the morphology of both the LMC and SMC, allowing me to identify warps, twists, and substructures in their stellar distributions. Using this approach, we have discovered a global azimuthal peripheral warp of the LMC, revealing large-scale distortions in its outer disk that likely result from past interactions with the Milky Way and the SMC. By constructing detailed distance maps, I can uncover signatures of tidal interactions, such as the extended arms and bridges that connect the Clouds to one another and to the Milky Way. This work not only provides a new view of the Magellanic Stellar geometry but also lays the foundation for all subsequent studies that rely on accurate distance measurements, from kinematics and chemical enrichment to star formation history analyses.

Ripples in the LMC Periphery

My upcoming paper in Science presents the first clear evidence of large-scale vertical ripples in the stellar periphery of the Large Magellanic Cloud (LMC). Using over 1.6 million red clump (RC) stars as precise distance indicators, we constructed the most accurate 3D maps of the LMC to date and discovered that its outer stellar populations are systematically offset by nearly 3 kpc from the central disk. With the aid of N-body simulations, we show that these distortions were induced by a close encounter with the Small Magellanic Cloud about 300 million years ago. This interaction generated vertical oscillations in the LMC disk with amplitudes of ~1.5 kpc and periods of ~400 Myr — signatures analogous to the ripples seen in the Milky Ways outer disk. These results provide a transformative view of how dwarf galaxy interactions reshape their hosts and establish the Magellanic Clouds as a nearby laboratory for studying tidal dynamics on galactic scales.

Star Formation History of the Magellanic Clouds

In addition to mapping the 3D structure of the Magellanic Clouds, I study their star formation histories (SFHs) to understand how these galaxies have evolved over time. Using deep photometric data from DELVE-MC, I reconstruct when and where stars formed across both the LMC and SMC. These analyses reveal spatial variations in stellar populations, from the ancient stars in their extended halos to younger episodes of star formation concentrated in their disks and tidal features. By comparing these SFHs with structural signatures like warps and ripples, I link the Clouds' internal evolution to their dynamical interactions with each other and with the Milky Way. Together, this work provides one of the most detailed pictures of how dwarf–dwarf and dwarf–host interactions drive galaxy evolution in the nearby Universe.

MAPS: MAgellanic Periphery Survey

MAPS is an extensive photometric and spectroscopic survey designed to target red, metal-poor giant stars to study the outer periphery regions of the Large and Small Magellanic Clouds (LMC/SMC). My research advisor (Dr. Nidever) is the PI of the project. The figure to the right shows a spatial map in Magellanic Stream coordinates of all the spectroscopic data from MAPS (\( \gtrsim \) 12 degrees) and APOGEE (\( \lesssim \) 12 degrees). The bulk of the data was acquired at the Cerro Tololo Inter-American Observatory (CTIO) with the Washington photometric system and hydra spectrograph on the 4-meter Blanco telescope, with some additional spectra acquired with the MIKE spectrograph on the Magellan-2 Clay 6.5 m telescope at Las Campanas Observatory. With the help of Gaia astrometry to obtain proper motions, I use MAPS to study the full 3D kinematics and chemistry of the outer periphery and halo-like populations of the LMC. Additionally, with the help of APOGEE for the inner disk, we can trace the evolution of the nominal disk kinematics to the perturbed periphery. I am currently working on writing MAPS paper I, outlining the survey description, target selection, data reduction, analysis procedures, and general periphery results. This paper should be published no later than 2025.

MAPS_Spatial_Plot
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LMC Northern Arm Kinematics

The "Northern Arm" of the LMC is a low-surface-brightness stellar overdensity region in the outer LMC that extends \( \gtrsim \) 10 kpc towards the east. Using MAPS, APOGEE, SDSS-V, and Gaia, my work aims to uncover the dynamic and structural properties of this perturbed region. By analyzing the 3D kinematics of giant stars, we can identify kinematically distinct populations that belong to this disturbed structure, which, for the first time, can be traced well within the LMC disk. See the figure to the left for an example of the kinematic peculiarity of the Northern Arm feature compared to the rest of the LMC disk and periphery (i.e. dark red feature in the north in the right panel). Using red clump stars for accurate distance measurements, we can study the kinematic trends over a length of 17 kpc of this feature. By comparing these findings with full N-body hydrodynamical simulations, we aim to better discern the LMC's past evolutionary history. The culmination of this project will be presented in a forthcoming paper.

LMC Stellar Halo Analysis

A long outstanding question over dwarf satellite galaxies (like the LMC) is whether or not they host accreted stellar halos. This begs the question if possesion of a stellar halo is dependent on disk size in spiral galaxies or total galaxy mass. To help answer this question I am using MAPS data to study a group of giant stars possibly belonging to a stellar halo of the LMC. By analyzing the kinematics, metallicities, and spatial distribution of these giant stars, my research aims to distinguish between stars that are part of an accreted halo and those that may have originated from the LMC's disk. This involves comparing observational data with theoretical models of galaxy evolution and accretion, as well as N-body simulations of the LMC's interactions with the SMC and the Milky Way. Identifying a distinct stellar halo around the LMC would not only provide insights into the formation history of the galaxy but also shed light on how dwarf galaxies evolve in the presence of larger host galaxies. These findings could help clarify whether stellar halos are a universal feature of galaxies or a product of specific environmental and evolutionary conditions.

Deep photometry of Large Magellanic Cloud (LMC)

Undergraduate Research at UMKC
Dr. Daniel McIntosh Webpage

RQEs

Recently Quenched Ellipticals (RQEs)

The role of star formation (SF) quenching in the hierarchical model of the development of galaxies in our universe has long been an unsolved puzzle. Using Galaxy Evolution Explorer (GALEX) + Sloan Digital Sky Survey (SDSS) data, I investigated SF signatures on a sample of 172 low-z (z ≤ 0.08) Recently Quenched Ellipticals (RQEs). This sample came from a parent catalog analyzed by McIntosh et al. 2014 (Figure to the left). Through a careful analysis of Near-Ultraviolet (NUV) light, I discovered 26 RQEs that have evidence of recent SF. Of the recent SF RQEs, they all are the lightest in stellar mass, bluest in color and faintest in r-band flux; which is in agreement with the hierarchical model of the development of galaxies. Furthermore, I have discovered at least 3 galaxies in this sample that can be considered actively star forming based on their urz color and location on NUVur color plots. Presumably, through an analysis of color-color-age plots, rejuvenation processes are the main cause of these active and recent SF ellipticals. Finally, I advise that the 3 ellipticals that were discovered to have active SF should be eliminated from further analyses of RQEs because they ultimately fail to be considered true RQEs. This research was concluded with writing a research report that can be found here

Major Merger Residuals Analysis

In this analysis, I analyzed the residual substructures of a representative sample of 500 galaxies obtained from a larger sample of 10,000 galaxies, all with stellar masses > 10^(9.5) M⊙ and redshift between 0.5 < z < 3. I develop 6 classification schemes of residual substructures that appear to be universal to a multitude of tidal features. Through running a tidal feature (TF) finder python code on a sample of these galaxies, I found that at least 3 of the 6 classification schemes are strongly supported by the results of the TF finder code and are applicable as ground truths for a residual classification Machine Learning (ML) software. Whereas, the other 3 classification schemes are not strongly supported by this analysis and should be analyzed further into whether or not they can be considered ground truths for a residual ML software. This research was concluded with writing a research report that can be found here

Residuals