Analysis of broad-lined Type Ic supernovae from the (intermediate) Palomar Transient Factory

¹ The Oskar Klein Centre, Department of Astronomy, Stockholm University, AlbaNova, 106 91 Stockholm, Sweden
e-mail: francesco.taddia@astro.su.se, ftadd@astro.su.se
² Cahill Center for Astrophysics, California Institute of Technology, Pasadena, CA 91125, USA
³ The School of Physics and Astronomy, Tel Aviv University, Tel Aviv 69978, Israel
⁴ Astrophysics Science Division, NASA Goddard Space Flight Center, Mail Code 661, Greenbelt, MD 20771, USA
⁵ Joint Space-Science Institute, University of Maryland, College Park, MD 20742, USA
⁶ Department of Astronomy, University of California, Berkeley, CA 94720-3411, USA
⁷ Miller Senior Fellow, Miller Institute for Basic Research in Science, University of California, Berkeley, CA 94720, USA
⁸ Department of Particle Physics and Astrophysics, Weizmann Institute of Science, Rehovot 76100, Israel
⁹ Las Cumbres Observatory, Goleta, CA 93117, USA
¹⁰ Department of Physics, University of California, Santa Barbara, CA 93106, USA
¹¹ Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138, USA
¹² Infrared Processing and Analysis Center, California Institute of Technology, Pasadena, CA 91125, USA
¹³ Lawrence Berkeley National Laboratory, 1 Cyclotron Road, MS 50B-4206, Berkeley, CA 94720, USA
¹⁴ Astrophysics Research Institute, Liverpool John Moores University, IC2, Liverpool Science Park, 146 Brownlow Hill, Liverpool, L3 5RF, UK
¹⁵ Department of Astronomy/Mount Laguna Observatory, San Diego State University, 5500 Campanile Drive, San Diego, CA 92812-1221, USA
¹⁶ Kavli IPMU (WPI), The University of Tokyo Institutes for Advanced Study, The University of Tokyo, Kashiwa, Chiba 277-8583, Japan
¹⁷ Samba TV, San Francisco, CA 94107, USA

Received: 15 October 2018
Accepted: 12 November 2018

Abstract

We study 34 Type Ic supernovae that have broad spectral features (SNe Ic-BL). This is the only SN type found in association with long-duration gamma-ray bursts (GRBs). We obtained our photometric data with the Palomar Transient Factory (PTF) and its continuation, the intermediate PTF (iPTF). This is the first large, homogeneous sample of SNe Ic-BL from an untargeted survey. Furthermore, given the high observational cadence of iPTF, most of these SNe Ic-BL were discovered soon after explosion. We present K-corrected Bgriz light curves of these SNe, obtained through photometry on template-subtracted images. We analyzed the shape of the r-band light curves, finding a correlation between the decline parameter Δm₁₅ and the rise parameter Δm₋₁₀. We studied the SN colors and, based on g − r, we estimated the host-galaxy extinction for each event. Peak r-band absolute magnitudes have an average of −18.6 ± 0.5 mag. We fit each r-band light curve with that of SN 1998bw (scaled and stretched) to derive the explosion epochs. We computed the bolometric light curves using bolometric corrections, r-band data, and g − r colors. Expansion velocities from Fe II were obtained by fitting spectral templates of SNe Ic. Bolometric light curves and velocities at peak were fitted using the semianalytic Arnett model to estimate ejecta mass M_ej, explosion energy E_K and ⁵⁶Ni mass M(⁵⁶Ni) for each SN. We find average values of M_ej = 4 ± 3 M_⊙, E_K = (7 ± 6)×10⁵¹ erg, and M(⁵⁶Ni)=0.31  ±  0.16 M_⊙. The parameter distributions were compared to those presented in the literature and are overall in agreement with them. We also estimated the degree of ⁵⁶Ni mixing using scaling relations derived from hydrodynamical models and we find that all the SNe are strongly mixed. The derived explosion parameters imply that at least 21% of the progenitors of SNe Ic-BL are compatible with massive (> 28 M_⊙), possibly single stars, whereas at least 64% might come from less massive stars in close binary systems.