The Carnegie Supernova Project II

Abstract

Supernova LSQ13abf was discovered soon after explosion by the La Silla-QUEST Survey and then followed by the Carnegie Supernova Project II at its optical and near-IR wavelengths. Our analysis indicates that LSQ13abf was discovered within two days of explosion and its first ≈10 days of evolution reveal a B-band light curve with an abrupt drop in luminosity. Contemporaneously, the V-band light curve exhibits a rise towards a first peak and the r- and i-band light curves show no early peak. The early light-curve evolution of LSQ13abf is reminiscent of the post-explosion cooling phase observed in the Type Ib SN 2008D, and the similarity between the two objects extends over weeks. Spectroscopically, LSQ13abf also resembles SN 2008D, with P Cygni He I features that strengthen over several weeks. Spectral energy distributions are constructed from the broad-bandphotometry, a UVOIR light curve is constructed by fitting black-body (BB) functions, and the underlying BB-temperature and BB-radius profiles are estimated. Explosion parameters are estimated by simultaneously fitting an Arnett model to the UVOIR light curve and the velocity evolution derived from spectral features, and an in addition to a post-shock breakout cooling model to the first two epochs of the bolometric evolution. This combined model suggests an explosion energy of 1.27 ± 0.23 × 1051 ergs, in addition to a relatively high ejecta mass of 5.94 ± 1.10 M⊙, a 56Ni mass of 0.16 ± 0.02 M⊙, and a progenitor-star radius of 28.0 ± 7.5 R⊙. The ejecta mass suggests the origins of LSQ13abf lie with a > 25 M⊙ zero-age-main-sequence mass progenitor and its estimated radius is three times larger compared to the result obtained from the same analysis applied to observations of SN 2008D, and nine times larger compared to SN 1999ex. Alternatively, a comparison of hydrodynamical simulations of ≳20−25 M⊙ zero-age-main-sequence progenitors that evolve to pre-supernova envelope masses of ≲10 M⊙ and extended (∼100 R⊙) envelopes also broadly match the observations of LSQ13abf.

A Diversity of Wave-driven Presupernova Outbursts

“…Recent examples of SNe with evidence for early interaction include Type II SNe such as SN 2016bkv (Nakaoka et al 2018), SN 2018zd (Zhang et al 2020), and many others (Khazov et al 2016;Förster et al 2018), and Type I SNe such as LSQ 13abf (Stritzinger et al 2020), LSQ 13ddu (Clark et al 2020), SN 2018bgv and SN 2018don (Lunnan et al 2020), SN 2018gep (Ho et al 2019), SN 2019dge (Yao et al 2020), and SN 2019uo (Gangopadhyay et al 2020). These SNe extend across virtually all spectroscopic classes of SNe (including Type II-P, II-L, IIn, Ib, Ic, Ibn, Ic-BL, superluminous Ic, etc.).…”

Model Light Curves for Type Ib and Ic Supernovae

“…7). Since the data in Stritzinger et al (2018a) and Stritzinger et al (2020) are given in CSP natural magnitudes, model light curves were computed accordingly. The faintest observed curve in Fig.…”

“…Fig. 16 shows a comparison of Model He6.00 (presupernova mass 4.44 M ) with Type Ib supernova LSQ13abf as reported by Stritzinger et al (2020). Photometry for LSQ13abf is taken from their Table 2, where magnitudes are given in the CSP natural system.…”

PTF11rka: an interacting supernova at the crossroads of stripped-envelope and H-poor superluminous stellar core collapses

“…Systematic searches and studies of SNe, made possible by large area sky surveys (e.g." Nicholl et al 2014;Lunnan et al 2018;Ho et al 2019;Moriya et al 2019a;Stritzinger et al 2020), are sampling the full parameter space, not only by covering wide ranges of luminosities and velocities, but also by broadening the temporal extent of the investigation, with efficient and timely reactions, that unveil the early behaviours and components, and sensitive lateepoch coverage that affords accurate nebular-phase investigations. This systematic approach makes unbiased detections possible and brings to evidence objects with intermediate properties that bridge seemingly separate groups.…”