2009/03/31 by Jeffrey M. Silverman, Paolo Mazzali, Ryan Chornock +5 · 2 citations
Physics and Astronomy · #Absorption (acoustics) #Absorption spectroscopy #Astronomy and Astrophysical Research #Astrophysics and Cosmic Phenomena #Ejecta #Gamma-ray bursts and supernovae #Helium #Optical spectra #Spectral line #Spectroscopy #Supernova #astro-ph.CO #astro-ph.HE #astro-ph.SR
paper · pdf · doi:10.1086/603653
11 pages, 5 figures, 3 tables, submitted to PASP
arxiv created 2009/05/22 · openalex publication_date 2009/06/16 · arxiv updated 2015/05/13 · openalex created_date 2016/06/24 · openalex updated_date 2026/08/05
Here we present previously unpublished optical spectra of supernova (SN) 2001ig, a Type IIb SN, from about a week after explosion until nearly one year later. The earliest spectrum consists of only a few broad absorption features, but soon more common Type II SN features including hydrogen P-Cygni profiles and helium absorption become apparent. At later times, as the H features fade and the He I absorption becomes more prominent, we observe the SN to transition from a Type II to a Type Ib. Finally, observations after 250 days past explosion show a nebular-phase SN spectrum with one of the largest magnesium to oxygen intensity ratios ever seen. Additionally, we present models of the late-time spectra which indicate that the inner ejecta consist of ~1.15 Msun of material, most of which (by mass) is in the form of oxygen, with ~0.13 Msun of Ni-56 and essentially no hydrogen.