Author : Samantha W. Brunker
Publisher :
ISBN 13 :
Total Pages : 0 pages
Book Rating : 4.4/5 (387 download)
Book Synopsis Green Peas and SAM by : Samantha W. Brunker
Download or read book Green Peas and SAM written by Samantha W. Brunker and published by . This book was released on 2022 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Green Pea galaxies are compact, extreme star-forming galaxies observed at intermediate redshifts (z = 0.15-0.4). Interest in the Green Pea galaxies has been steadily growing, especially once the Green Peas were discovered to exhibit escaping ionizing radiation. Green Pea galaxies have become prime analogs for studying the contributions of star-forming galaxies to reionization. Despite the intense interest in these unusual galaxies, there are several open questions regarding the nature of the Green Peas. This dissertation focuses on the KISSR Green Pea galaxies with the aim of addressing three outstanding questions regarding the Green Peas: (1) What is the range of characteristic properties of the Green Peas? (2) What triggered the starburst activity in the Green Peas? and (3) Why are the Green Peas low-metallicity systems? First, we confirm that the KISSR Green Pea galaxies are consistent with the properties of the original Green Pea galaxy sample. We show that the KISSR Green Peas are a factor of 17 times brighter than a typical star-forming galaxy of the same mass, which means 94% of the light is coming from the starburst population. Second, we designed and carried out a redshift survey using the Hydra multi-fiber positioner and Bench Spectrograph on the WIYN 3.5m telescope, which we used to investigate what impact a Green Pea's environment has on its star formation. We observed and measured redshifts for 1312 galaxies distributed between the 13 KISSR Green Pea fields. We used three density analysis techniques to quantify the galaxian densities around the KISSR Green Peas. Based on the combined results from these density analyses, we sorted the KISSR Green Peas into specific environment categories. We find that none of the KISSR Green Peas live in higher-density environments. A majority of them live in voids or in low-density environments tending towards isolation. We compare the measured densities for each Green Pea with several of their key physical properties. We find that there is no correlation between the galaxy properties and the galaxian densities, and we conclude that environment is not a strong factor in driving the star-formation activity in the KISSR Green Peas. Lastly, we present an analysis of the chemical compositions of the KISSR Green Peas. We successfully measured the weak [O III]A4363 emission line in 9 of the 13 KISSR Green Peas at a level that resulted in robust direct-method abundances. We confirm that the KISSR Green Peas are low-metallicity systems. We found that the Green Peas have slightly elevated N/O ratios, for which we propose a chemical evolution history that deviates from what is expected for "normal" star-forming galaxies. The multifaceted approach to studying Green Pea galaxies presented in this dissertation will provide a basis for a better understanding of the nature of Green Peas and how they fit into the larger narrative of galaxy formation and evolution.