The Carnegie Supernova Project I

STRITZINGER, M. D.; TADDIA, F.; BURNS, C. R.; PHILLIPS, M. M.; BERSTEN, M.; CONTRERAS, C.; FOLATELLI, G.; HOLMBO, S.; HSIAO, E. Y.; HOEFLICH, P.; LELOUDAS, G.; MORRELL, N.; SOLLERMAN, J.; SUNTZEFF, N. B.

ASTRONOMY AND ASTROPHYSICS

EDP SCIENCES S A

Año: 2018 vol. 609

0004-6361

e aim to improve upon contemporary methods to estimate host-galaxyreddening of stripped-envelope (SE) supernovae (SNe). To this end theCarnegie Supernova Project (CSP-I) SE SN photometry data release,consisting of nearly three dozen objects, is used to identify aminimally reddened sub-sample for each traditionally definedspectroscopic sub-type (i.e., SNe IIb, SNe Ib, SNe Ic). Inspection ofthe optical and near-infrared (NIR) colors and color evolution of theminimally reddened sub-samples reveals a high degree of homogeneity,particularly between 0 d to +20 d relative to B-band maximum. Thismotivated the construction of intrinsic color-curve templates, whichwhen compared to the colors of reddened SE SNe, yields an entire suiteof optical and NIR color excess measurements. Comparison ofoptical/optical vs. optical/NIR color excess measurements indicates themajority of the CSP-I SE SNe suffer relatively low amounts of reddening(i.e., E(B-V)host< 0.20 mag) and we find evidence fordifferent RVhost values among different SE SN.Fitting the color excess measurements of the seven most reddened (i.e.,E(B-V)host> 0.20 mag) objects with the Fitzpatrick (1999,PASP, 111, 63) reddening law model provides robust estimates of the hostvisual-extinction AVhost andRVhost. In the case of the SE SNe with relativelylow amounts of reddening, a preferred value ofRVhost is adopted for each sub-type, resulting inestimates of AVhost through Fitzpatrick (1999)reddening law model fits to the observed color excess measurements. Ouranalysis suggests SE SNe reside in galaxies characterized by a range ofdust properties. We also find evidence that SNe Ic are more likely tooccur in regions characterized by larger RVhostvalues compared to SNe IIb/Ib and they also tend to suffer moreextinction. The later finding is consistent with work in the literaturesuggesting SNe Ic tend to occur in regions of on-going star formation.Based on observations collected at Las Campanas Observatory.