Studying Global and Local Star Formation Processes with Young Massive Stars in NGC 6946

Abstract

I analyze resolved near-ultraviolet (NUV) stellar photometry of star-forming galaxy NGC 6946 (The Fireworks Galaxy) taken with the Hubble Space Telescope's (HST) Wide Field Camera 3 (WFC3) with F275W and F336W filters to put new constraints on the relationships between the spatial distribution of ages, formation rate, masses, colors, and luminosity for massive stars and massive star clusters. In Chapter 2, we observe a correlation between age and density in the spiral arms and test diagnostics for star formation rate (SFR) and whether they are consistent with the unusually high observed rate of supernovae (10 in the past century). In Chapter 3, I modify a computer-vision algorithm to automate cluster candidate finding and produce a cluster and association candidate catalog. I measure the luminosity, effective radius, and color of each of the candidates. With the catalog obtained in Chapter 3, in Chapter 4, I constrain the cluster mass-radius relation and mass function of clusters. We measure the age of the clusters and determine the cluster formation efficiency of NGC 6946. We will publicly release this new clustering algorithm to the community and this observational data enabling detailed comparisons to numerical simulations. In Chapter 5, my future work, I discuss my progress and plans to measure an additional 13 bands ($\sim$200 visits) of archival optical and infrared (IR) HST WFC3 and Advanced Camera for Surveys (ACS) photometry of individual stars and clusters covering some areas in NGC 6946. With the planned stellar photometry catalog, I will fit spectral energy distributions (SEDs) for over 8 million stars in NGC 6946 to investigate how local environments and large scale mechanisms influence the formation of stars.