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1	A New Set of Spectroscopic Metallicity Calibrations for RR Lyrae Variable Stars Spalding, Eckhart 01 January 2014 (has links) RR Lyrae stars are old, iron-poor, Helium-burning variable stars. RR Lyraes are extremely useful for tracing phase-space structures and metallicities within the galaxy because they are easy to identify, have consistent luminosities, and are found in large numbers in the galactic disk, bulge, and halo. Here we present a new set of spectroscopic metallicity calibrations that use the equivalent widths of the Ca II K, Hγ, and Hδ lines to calculate metallicity values. Applied to spectroscopic survey data, these calibrations will help shed light on the evolution of the Milky Way and other galaxies. RR Lyraes metallicity calibration spectroscopy galactic halo Sloan Digital Sky Survey
2	Characterizing AGN Influence on the Calculated Metallicities of Adjacent Star-Forming Spaxels Khelil, Aidan 08 November 2022 (has links) No description available. Astronomy Astrophysics Physics Galaxy Metallicity Spaxel AGN Sloan Digital Sky Survey SDSS Galactic metallicities Astronomy Astrophysics Border spaxels Metallicity calibration
3	RR LYRAE CALIBRATION USING SDSS, SINGLE-EPOCH SPECTROSCOPY Long, Stacy 01 January 2018 (has links) I use single-epoch, SDSS spectroscopy of RR Lyraes identified in the Catalina survey to separate the spectra into same-temperature groups. Then I draw temperature-phase diagrams of the groups. I find shocked stars, improperly phased stars, low amplitude stars, and a few that are more likely eclipsing binaries. The RR Lyraes are then given precise metallicities by measurements of the CaII K and H-β, H-γ, and H-δ lines. This leads to better distance measurements, which allow me to confirm a distinction between the inner and outer galactic halo. stars variables RR Lyrae surveys Sloan surveys Catalina metallicity calibration galactic halo Astrophysics and Astronomy Physical Sciences and Mathematics

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