Type Ia Supernovae in the Ultraviolet, Optical, and Near-Infrared
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We present an ultraviolet (UV) spectroscopic atlas containing 91 spectra of 22 unique Type Ia supernovae (SNe Ia). The spectra were observed using the Ultraviolet/Optical Telescope (UVOT) onboard the Swift space telescope. We present a new technique of decontaminating UVOT grism spectra, which we apply to 40 of the spectra in our sample. We present the first UV spectroscopic series of a peculiar 1999aa-like SN Ia, iPTF14bdn, and compare to normal SNe in our sample. We find this SN to be very blue at early times due to a bright feature between 2800 - 3200Å. We attribute this to a lower UV opacity caused by higher temperatures above the SN photosphere, likely due to a greater quantity of ^56Ni in this region. We also identify the spectroscopic feature differences between 2700 - 3300Å responsible for the near-UV (NUV) photometric diversity. Comparison of these features to model data suggest that NUV-bluer SNe result from lower metal abundances in the outer ejecta layers. We combine our UV spectral atlas with UV, optical and NIR photometry, and spectra to generate a UV-O-IR spectral series atlas for 8 SNe Ia near peak brightness. The UV-O-IR SEDs represent time evolution within -10 to +30 days of peak brightness, decline rates between 0.9 < Δm15(B) < 1.8, and UV subclassification (when known). Using these data, we calculate integrated bolometric luminosities and synthesized ^56Ni masses. We demonstrate that our UV-O-IR SEDs provide an improved method of calculating K-corrections for B-band optical photometry, and present an analysis of SNe Ia UV K-corrections. We present a method of calculating bolometric corrections which take the SNe decline rates into account for SNe near peak brightness.
Smitka, Michael Thomas (2016). Type Ia Supernovae in the Ultraviolet, Optical, and Near-Infrared. Doctoral dissertation, Texas A & M University. Available electronically from