A1 Refereed original research article in a scientific journal
450 d of Type II SN 2013ej in optical and near-infrared
Authors: Yuan F, Jerkstrand A, Valenti S, Sollerman J, Seitenzahl IR, Pastorello A, Schulze S, Chen TW, Childress MJ, Fraser M, Fremling C, Kotak R, Ruiter AJ, Schmidt BP, Smartt SJ, Taddia F, Terreran G, Tucker BE, Barbarino C, Benetti S, Elias-Rosa N, Gal-Yam A, Howell DA, Inserra C, Kankare E, Lee MY, Li KL, Maguire K, Margheim S, Mehner A, Ochner P, Sullivan M, Tomasella L, Young DR, Young DR
Publisher: OXFORD UNIV PRESS
Publication year: 2016
Journal: Monthly Notices of the Royal Astronomical Society
Journal name in source: MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
Journal acronym: MON NOT R ASTRON SOC
Volume: 461
Issue: 2
First page : 2003
Last page: 2018
Number of pages: 16
ISSN: 0035-8711
DOI: https://doi.org/10.1093/mnras/stw1419
We present optical and near-infrared photometric and spectroscopic observations of SN 2013ej, in galaxy M74, from 1 to 450 d 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-V =-17.6) but a small 56Ni production of similar to 0.023 M-circle dot. Its photospheric evolution is similar to other Type II SNe, with shallow absorption in the H a profile typical for a Type IIL. During transition to the radioactive decay tail at similar to 100 d, 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 Co-56 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-ZAMS = 12-15 M-circle dot 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.
