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Proving Evolution of Galaxy Dark Matter Since Cosmic Noon

Presentation #425.05 in the session “Dark Matter & Dark Energy”.

Published onJan 11, 2021
Proving Evolution of Galaxy Dark Matter Since Cosmic Noon

The purpose of the research was to quantify the dark matter present in galaxies since Cosmic Noon by modeling as a function of time. Dark matter is difficult to detect because it does not interact with electromagnetic radiation. Data was utilized from the intersection of two astronomical surveys — Hubble Space Telescope’s CANDELS survey, and Keck Telescope’s HALO7D Survey. The research involved data science, creating plots to analyze data from subfields of the surveys. First, data was characterized based on select parameters: redshift, apparent magnitude, star formation rate, and log masses of galaxies. These parameters, once plotted, visually permitted the filtering out of data that corresponded to stars, dim galaxies, and bright absorption line galaxies, leaving bright emission line galaxies as the focus of the data set. The spectral data of these emission line galaxies were then mathematically modeled, fitting gaussian curves with the OII, OIII, and HBeta spectral lines. The center and standard deviation of each galaxy were extracted to use in calculations of the galaxy’s velocity dispersion and dynamical mass. To ultimately quantify the amount of dark matter, the stellar mass of each galaxy was plotted against its dynamical mass. Through visual interpretation, it was concluded that approximately 90% or more of each galaxy’s mass came from dark matter regardless of its distance to Earth.

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