Volume 609, January 2018
|Number of page(s)||22|
|Published online||05 February 2018|
The Carnegie Supernova Project I
Methods to estimate host-galaxy reddening of stripped-envelope supernovae ⋆
1 Department of Physics and Astronomy, Aarhus University, Ny Munkegade 120, 8000 Aarhus C, Denmark
2 The Oskar Klein Centre, Department of Astronomy, Stockholm University, AlbaNova, 10691 Stockholm, Sweden
3 Observatories of the Carnegie Institution for Science, 813 Santa Barbara St., Pasadena, CA 91101, USA
4 Carnegie Observatories, Las Campanas Observatory, Casilla 601, La Serena, Chile
5 Facultad de Ciencias Astronómicas y Geofísicas, Universidad Nacional de La Plata, Paseo del Bosque S/N, B1900 FWA La Plata, Argentina
6 Instituto de Astrofísica de La Plata (IALP), CONICET, Argentina
7 Kavli Institute for the Physics and Mathematics of the Universe, Todai Institutes for Advanced Study, University of Tokyo, 5-1-5 Kashiwanoha, Kashiwa, Chiba 277-8583, Japan
8 Department of Physics, Florida State University, 77 Chieftain Way, Tallahassee, FL 32306, USA
9 Department of Particle Physics and Astrophysics, Weizmann Institute of Science, Rehovot 7610001, Israel
10 George P. and Cynthia Woods Mitchell Institute for Fundamental Physics and Astronomy, Department of Physics and Astronomy, Texas A&M University, College Station, TX 77843, USA
Received: 22 March 2017
Accepted: 31 July 2017
We aim to improve upon contemporary methods to estimate host-galaxy reddening of stripped-envelope (SE) supernovae (SNe). To this end the Carnegie Supernova Project (CSP-I) SE SN photometry data release, consisting of nearly three dozen objects, is used to identify a minimally reddened sub-sample for each traditionally defined spectroscopic sub-type (i.e., SNe IIb, SNe Ib, SNe Ic). Inspection of the optical and near-infrared (NIR) colors and color evolution of the minimally reddened sub-samples reveals a high degree of homogeneity, particularly between 0 d to +20 d relative to B-band maximum. This motivated the construction of intrinsic color-curve templates, which when compared to the colors of reddened SE SNe, yields an entire suite of optical and NIR color excess measurements. Comparison of optical/optical vs. optical/NIR color excess measurements indicates the majority 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 for different 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 host visual-extinction AVhost and RVhost. In the case of the SE SNe with relatively low amounts of reddening, a preferred value of RVhost is adopted for each sub-type, resulting in estimates of AVhost through Fitzpatrick (1999) reddening law model fits to the observed color excess measurements. Our analysis suggests SE SNe reside in galaxies characterized by a range of dust properties. We also find evidence that SNe Ic are more likely to occur in regions characterized by larger RVhost values compared to SNe IIb/Ib and they also tend to suffer more extinction. The later finding is consistent with work in the literature suggesting SNe Ic tend to occur in regions of on-going star formation.
Key words: supernovae: general
© ESO, 2018
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