The Carnegie Supernova Project I

TADDIA, F.; STRITZINGER, M. D.; BERSTEN, M.; BARON, E.; BURNS, C.; CONTRERAS, C.; HOLMBO, S.; HSIAO, E. Y.; MORRELL, N.; PHILLIPS, M. M.; SOLLERMAN, J.; SUNTZEFF, N. B.

ASTRONOMY AND ASTROPHYSICS

EDP SCIENCES S A

Año: 2018 vol. 609

0004-6361

Stripped-envelope (SE) supernovae (SNe) include H-poor (Type IIb),H-free (Type Ib), and He-free (Type Ic) events thought to be associatedwith the deaths of massive stars. The exact nature of their progenitorsis a matter of debate with several lines of evidence pointing towardsintermediate mass (Minit< 20 M⊙) stars inbinary systems, while in other cases they may be linked to singlemassive Wolf-Rayet stars. Here we present the analysis of the lightcurves of 34 SE SNe published by the Carnegie Supernova Project (CSP-I)that are unparalleled in terms of photometric accuracy and wavelengthrange. Light-curve parameters are estimated through the fits of ananalytical function and trends are searched for among the resulting fitparameters. Detailed inspection of the dataset suggests a tentativecorrelation between the peak absolute B-band magnitude andΔm15(B), while the post maximum light curves reveals acorrelation between the late-time linear slope andΔm15. Making use of the full set of optical and near-IRphotometry, combined with robust host-galaxy extinction corrections,comprehensive bolometric light curves are constructed and compared toboth analytic and hydrodynamical models. This analysis finds consistentresults among the two different modeling techniques and from thehydrodynamical models we obtained ejecta masses of1.1-6.2M⊙, 56Ni masses of0.03-0.35M⊙, and explosion energies (excluding two SNeIc-BL) of 0.25-3.0 × 1051 erg. Our analysis indicatesthat adopting κ = 0.07 cm2 g-1 as the meanopacity serves to be a suitable assumption when comparing Arnett-modelresults to those obtained from hydrodynamical calculations. We also findthat adopting He I and O I line velocities to infer the expansionvelocity in He-rich and He-poor SNe, respectively, provides ejectamasses relatively similar to those obtained by using the Fe II linevelocities, although the use of Fe II as a diagnostic does imply higherexplosion energies. The inferred range of ejecta masses are compatiblewith intermediate mass (MZAMS ≤ 20M⊙)progenitor stars in binary systems for the majority of SE SNe.Furthermore, our hydrodynamical modeling of the bolometric light curvessuggests a significant fraction of the sample may have experiencedsignificant mixing of 56Ni, particularly in the case of SNeIc.