2016/05/19 by Fang Yuan, A. Jerkstrand, S. Valenti +31 · 1 citation
Physics and Astronomy · #astro-ph.SR
paper · pdf · doi:10.1093/mnras/stw1419
23 pages, 18 figures, submitted to MNRAS
arxiv created 2016/05/19 · arxiv updated 2016/07/27
We present optical and near-infrared photometric and spectroscopic observations of SN 2013ej, in galaxy M74, from 1 to 450 days after the explosion. SN 2013ej is a hydrogen-rich supernova, classified as a Type IIL due to its relatively fast decline following the initial peak. It has a relatively high peak luminosity (absolute magnitude M_\rmV = -17.6) but a small 56Ni production of ~0.023 M_\odot. Its photospheric evolution is similar to other Type II SNe, with shallow absorption in the Hα profile typical for a Type IIL. During transition to the radioactive decay tail at ~100 days, we find the SN to grow bluer in B - V colour, in contrast to some other Type II supernovae. At late times, the bolometric light curve declined faster than expected from 56Co decay and we observed unusually broad and asymmetric nebular emission lines. Based on comparison of nebular emission lines most sensitive to the progenitor core mass, we find our observations are best matched to synthesized spectral models with a M_\rmZAMS = 12 - 15 M_\odot progenitor. The derived mass range is similar to but not higher than the mass estimated for Type IIP progenitors. This is against the idea that Type IIL are from more massive stars. Observations are consistent with the SN having a progenitor with a relatively low-mass envelope.