We present 637 low-redshift optical spectra collected by the Berkeley Supernova Ia Program (BSNIP) between 2009 and 2018, almost entirely with the Kast double spectrograph on the Shane 3 m telescope at Lick Observatory. We describe our automated spectral classification scheme and arrive at a final set of 626 spectra (of 242 objects) that are unambiguously classified as belonging to Type Ia supernovae (SNe Ia). Of these, 70 spectra of 30 objects are classified as spectroscopically peculiar (i.e. not matching the spectral signatures of 'normal' SNe Ia) and 79 SNe Ia (covered by 328 spectra) have complementary photometric coverage. The median SN in our final set has one epoch of spectroscopy, has a redshift of 0.0208 (with a low of 0.0007 and high of 0.1921), and is first observed spectroscopically 1.1 d after maximum light. The constituent spectra are of high quality, with a median signal-to-noise ratio of 31.8 pixel-1, and have broad wavelength coverage, with ∼95 per cent covering at least 3700-9800 Å. We analyse our data set, focusing on quantitative measurements (e.g. velocities, pseudo-equivalent widths) of the evolution of prominent spectral features in the available early-time and latetime spectra. The data are available to the community, and we encourage future studies to incorporate our spectra in their analyses.
Bibliographical noteFunding Information:
We thank Bela Abolfathi, Louis Abramson, Iair Arcavi, Roberto Assef, Aaron Barth, Vardha Bennert, Andrew Bigley, Peter Blan-chard, Joshua Bloom, Benjamin Boizelle, Azalee Bostroem, Andrew Brandel, Michael Busch, Zheng Cai, Gabriela Canalizo, Dan Carson, Jieun Choi, Daniel Cohen, Michael Cooper, Maren Cosens, Antonino Cucchiara, Aleks Diamond-Stanic, Subo Dong, Sean Fillingham, Ryan Foley, Mohan Ganeshalingam, Elinor Gates, Jenny Greene, Christopher Griffith, Kyle Hiner, Sebastian Hoenig, Griffin Hosseinzadeh, Yiseul Jeon, Caitlin Johnson, Daniel Kasen, Minkyu Kim, Mariana Lazarova, David Levitan, Matthew Malkan, Christina Manzano-King, Bruce Margon, Carl Melis, Allison Mer-ritt, Adam Miller, Maryam Modjaz, Adam Morgan, Alekzandir Morton, Robin Mostardi, My Nguyen, Peter Nugent, Liuyi Pei, Daniel Perley, Dovi Poznanski, Armin Rest, Jacob Rex, Roger Romani, Liming Rui, Frank Serduke, Remington Sexton, Jaejin Shin, Marijana Smailagic, Alessandro Sonnenfeld, Thea Steele, Tommaso Treu, Vivian U, Stefano Valenti, Alex Vogler, Jonelle Walsh, Marie Wingyee Lau, Gabor Worseck, Fang Yuan, Sameen Yunus, Yinan Zhu, and others for their assistance with some of the observations over the past decade presented in this paper. We would also like to express our gratitude to the staffs at the Lick and Keck Observatories for their support, and our anonymous referee whose careful reading and constructive comments improved the manuscript. KAIT and its ongoing operation were made possible by donations from Sun Microsystems, Inc., the Hewlett-Packard Company, AutoScope Corporation, Lick Observatory, the NSF, the University of California, the Sylvia & Jim Katzman Foundation, and the TABASGO Foundation.
5IRAF is distributed by the National Optical Astronomy Observatory, which is operated by AURA, Inc., under a cooperative agreement with the U.S. National Science Foundation (NSF). 6Kast and LRIS data are currently reduced with KASTSHIV (Shivvers et al. 2016)and LPIPE (Perley 2019), respectively. Prior to October 2016, a number of LRIS spectra were reduced with purpose-built routines from the Carnegie PYTHON (CARPY) Distribution (Kelson et al. 2000; Kelson 2003).
BES thanks Marc J. Staley for generously providing fellowship funding, and S. L. Watkins and C. W. Fink for their helpful suggestions during the development of RESPEXT. MLG acknowledges support from the DIRAC Institute in the Department of Astronomy at the University of Washington. The DIRAC Institute is supported through generous gifts from the Charles and Lisa Simonyi Fund
for Arts and Sciences, and the Washington Research Foundation. XGW is supported by the National Natural Science Foundation of China (NSFC grant 11673006), and the Guangxi Science Foundation (grants 2016GXNSFFA380006 and 2017AD22006). XW is supported by the National Natural Science Foundation of China (NSFC grants 11325313, 11633002, and 11761141001), and the National Program on Key Research and Development Project (grant 2016YFA0400803).
This research has made use of the NASA/IPAC Extragalactic Database (NED), which is operated by the Jet Propulsion Laboratory, California Institute of Technology, under contract with NASA. Some of the data presented herein were obtained at the W. M. Keck Observatory, which is operated as a scientific partnership among the California Institute of Technology, the University of California, and the National Aeronautics and Space Administration (NASA). The Observatory was made possible by the generous financial support of the W. M. Keck Foundation. The authors wish to recognize and acknowledge the very significant cultural role and reverence that the summit of Maunakea has always had within the indigenous Hawaiian community. We are most fortunate to have the opportunity to conduct observations from this mountain.
© 2020 The Author(s).
- Cosmology: Observations
- Distance scale
- Supernovae: General
- Techniques: Spectroscopic