Astrophysics Seminar: Samantha Brunker, IU Bloomington


Location: 184 Nieuwland Science Hall (View on map )

Green Peas and Sam: A Multifaceted Approach to Studying Extreme, Star-Forming Green Pea Galaxies

Samantha Brunker
IU Bloomington

Green Pea galaxies are compact, extreme star-forming galaxies observed at intermediate redshifts (z ~ 0.15-0.4). Here we present analyses focusing on three aspects of Green Peas with the goal of better understanding their nature and origins. The first attempts to determine if the Green Pea environments can help to explain the cause of the starburst events. We present results from a redshift survey of field galaxies within a one-degree field of view around a large sample of Green Pea galaxies. We measure redshifts for ~100-120 galaxies in each of the fields and combine these with redshifts from the literature in order to analyze the densities of galaxies near the Green Peas. We are also interested in the chemical compositions of the Green Pea galaxies. We have obtained deep, high quality spectra of each Green Pea in our sample. These spectra allow us to measure the temperature sensitive [O III] 4363 emission line and derive direct abundances for ~30 of 39 Green Peas. Our preliminary abundance measurements are consistent with previous observations of Green Peas as low-metallicity systems. The third analysis we will present pertains to the UV properties of our Green Peas. We have obtained FUV spectra covering both the LyA emission line and LyC region as well as NUV imaging for 5 Green Pea galaxies in our sample using HST. We are investigating their LyC and LyA escape fractions, as well as their NUV morphologies. Our sample was specifically chosen to have a range of properties, including higher mass Green Peas than have been previously observed, so that we can better understand the systematics of LyC and LyA emission from this class of galaxy. Our multifaceted approach to studying Green Pea galaxies will help us to better understand how they fit into the narrative of galaxy formation and evolution.

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