Direct Analysis of Type Ia Supernovae Observed by The Nearby Supernova Factory
Résumé
Over the past four years, the Nearby Supernova Factory (SNfactory) has obtained hundreds of time-series spectra of Type Ia supernovae (SNe Ia) using its SuperNova Integral Field Spectrograph (SNIFS). This dataset is a promising resource for improving our understanding of SN Ia explosion physics and progenitor models --- key issues that, if resolved, could further improve the utility of and confidence in SNe Ia as reliable cosmological distance indicators. Using a new, automated direct analysis code we have developed (SYNAPPS), we have commenced a systematic study of the SNfactory spectroscopic data set. SYNAPPS solves for a highly parameterized synthetic spectrum consistent with the observed spectrum, enabling line identification and ejecta velocity measurements, while treating line-blending explicitly. These results provide important constraints on stellar explosion models. We present preliminary results including, for example, an investigation of some early-phase spectra, and examine trends in spectral behavior noted previously by others. We also address future directions for code development to bring about a deeper physics analysis of the data.