2015/05/19 by Brian W. Mulligan, Mulligan, Brian W., J. C. Wheeler +1
Physics and Astronomy · #Astro and Planetary Science #Astrophysics of Galaxies (astro-ph.GA) #FOS: Physical sciences #Gamma-ray bursts and supernovae #High Energy Astrophysical Phenomena (astro-ph.HE) #Solar and Stellar Astrophysics (astro-ph.SR)
paper · pdf · doi:10.48550/arxiv.1505.05145
openalex publication_date 2015/05/19 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
High-velocity features (HVF), especially of Ca II, are frequently seen in\nType Ia supernova observed prior to B-band maximum (Bmax). These HVF evolve in\nvelocity from more than 25,000 km/s, in the days after first light, to about\n18,000 km/s near Bmax. To recreate the evolution of the Ca II near-infrared\ntriplet (CaNIR) HVF in SN 2011fe, we consider the interaction between a model\nType Ia supernova and compact circumstellar shells with masses between 0.003\nsolar masses and 0.012 solar masses. We fit the observed CaNIR feature using\nsynthetic spectra generated from the models using syn++. The CaNIR feature is\nbetter explained by the supernova model interacting with a shell than the model\nwithout a shell, with a shell of mass 0.005 solar masses tending to be better\nfitting than the other shells. The evolution of the optical depth of CaNIR\nsuggests that the ionization state of calcium within the ejecta and shell is\nnot constant. We discuss the method used to measure the observed velocity of\nCaNIR and other features and conclude that HVF or other components can be\nfalsely identified. We briefly discuss the possible origin of the shells and\nthe implications for the progenitor system of the supernova.\n