Date of Graduation

5-2017

Level of Access

Open Access

Degree Name

Bachelor of Science

Department or Program

Physics and Astronomy

First Advisor

Diamond-Stanic, Aleksandar

Abstract

Why are galaxies so bad at forming stars? Observations and simulations of how efficiently galaxies can collapse cold, dense gas into stars differ by an order of magnitude. Scientists turn to processes that inject energy or momentum into galaxies to prevent gas from cooling and forming stars. Our research investigates whether radiation or ram pressure from stars could produce high-velocity outflows of cold, dense gas and reduce galactic star formation. Understanding why galaxies struggle to form stars out of normal matter will inform our knowledge of the galactic lifecycle, and resolve the inefficiency dilemma between observations and simulations. Typical outflow velocities from star-forming galaxies range from 100 to 500 km / s , but some massive, compact galaxies have been observed to eject gas at speeds exceeding 1000 km / s . Outflows like these are typically attributed to an active galactic nucleus (AGN), but there is no evidence for AGN activity for most galaxies in this sample from optical, infrared, and x-ray observations. We present an investigation of whether or not the radiation pressure from a recent starburst event could be responsible for the outflows in each of a sample of 12 galaxies. In particular, we focus on observations at rest-frame U, V, and J wavelengths with the Wide Field Camera 3 (WFC3) on the Hubble Space Telescope (HST) that were designed to spatially resolve the mass distribution for these massive galaxies.

Components of Thesis

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