Development of a Transfer Box for the MLOF telescope and studies of host galaxies of supernova siblings.

Abstract

This thesis consists of two parts, including the recent upgrade of the Mount Lemmon Observing Facility (MLOF), and a study of the gas-phase properties of host galaxies of supernova (SN) siblings. MLOF, located near Tucson, AZ, sits atop Mt. Lemmon. This telescope, built in 1970, has proved itself useful over the years as an infrared-optimized telescope. Until recently, all observing with this telescope had to be done on site. However, in 2019, an upgrade to roboticize this telescope was proposed. This upgrade includes the installation of a new, robotic operating system for the telescope, allowing for remote observing. To facilitate remotely switching between types of observations, a Transfer Box has been designed and built. This Transfer Box has six camera ports and one instrument attachment and is bolted directly to the back end of the MLOF telescope. Inside this Transfer Box is a series of mirrors to guide the telescope light to the desired set of cameras and dichroics to split the light into the appropriate wavelength for each camera. In this thesis, I describe my design of this Transfer Box. This upgrade to MLOF should allow it to continue in its usefulness in serving the astronomy community for many years to come.The second part of this thesis is a study of the gas-phase properties of host galaxies of supernova siblings. Over the past century, thousands of SNe have been observed. In a growing number of cases, multiple SNe have been discovered in individual galaxies. When this occurs, they are referred to as SN siblings. We examine the dependence of the properties of SNe siblings on their host galaxies. To do this, optical spectra of 59 host galaxies of multiple core-collapse SNe were obtained with the Bok telescope and the CALIFA survey. When placed on the Baldwin-Phillips-Terlevich (BPT) diagram, a strong majority of the spectra of these galaxies fall within the composite region. Additionally, comparing the distributions of [NII] λ6583/Hα between galaxies that have hosted a majority SN Ibc and galaxies that have hosted a majority SN II, we find on average, with a statistically significant difference (KS test p-value = 0.044), that the galaxies that have hosted a majority SN Ibc have higher [NII] λ6583/Hα ratios. This difference may arise from either AGN or LINER contributions or from a higher average metallicity of SN Ibc hosts, or perhaps from both. This work also compares the inferred oxygen abundance and ionization parameters for the hosts of SN Ibc and the hosts of SN II that fall within the Star Forming region on the BPT diagram. Again, we find statistically significant differences for oxygen abundance (p=0.008) and ionization (p=0.001). When we compare SN Ib hosts and SN II hosts, we still find a statistically significant difference for oxygen abundance (p=0.030) and ionization (p=0.006). Furthermore, we also compare the Hα equivalent width distributions, but we find no statistically significant difference.