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Open Access Publications from the University of California

ZTF Early Observations of Type Ia Supernovae. I. Properties of the 2018 Sample

  • Author(s): Yao, Yuhan
  • Miller, Adam A
  • Kulkarni, SR
  • Bulla, Mattia
  • Masci, Frank J
  • Goldstein, Daniel A
  • Goobar, Ariel
  • Nugent, Peter
  • Dugas, Alison
  • Blagorodnova, Nadia
  • Neill, James D
  • Rigault, Mickael
  • Sollerman, Jesper
  • Nordin, J
  • Bellm, Eric C
  • Cenko, S Bradley
  • De, Kishalay
  • Dhawan, Suhail
  • Feindt, Ulrich
  • Fremling, C
  • Gatkine, Pradip
  • Graham, Matthew J
  • Graham, Melissa L
  • Ho, Anna YQ
  • Hung, T
  • Kasliwal, Mansi M
  • Kupfer, Thomas
  • Laher, Russ R
  • Perley, Daniel A
  • Rusholme, Ben
  • Shupe, David L
  • Soumagnac, Maayane T
  • Taggart, K
  • Walters, Richard
  • Yan, Lin
  • et al.

© 2019. The American Astronomical Society. All rights reserved. Early-time observations of Type Ia supernovae (SNe Ia) are essential to constrain the properties of their progenitors. In this paper, we present high-quality light curves of 127 SNe Ia discovered by the Zwicky Transient Facility (ZTF) in 2018. We describe our method to perform forced point-spread function photometry, which can be applied to other types of extragalactic transients. With a planned cadence of six observations per night (three g + three r), all of the 127 SNe Ia are detected in both g and r bands more than 10 days (in the rest frame) prior to the epoch of g-band maximum light. The redshifts of these objects range from z = 0.0181 to 0.165; the median redshift is 0.074. Among the 127 SNe, 50 are detected at least 14 days prior to maximum light (in the rest frame), with a subset of nine objects being detected more than 17 days before g-band peak. This is the largest sample of young SNe Ia collected to date; it can be used to study the shape and color evolution of the rising light curves in unprecedented detail. We discuss six peculiar events in this sample: one 02cx-like event ZTF18abclfee (SN 2018crl), one Ia-CSM SN ZTF18aaykjei (SN 2018cxk), and four objects with possible super-Chandrasekhar mass progenitors: ZTF18abhpgje (SN 2018eul), ZTF18abdpvnd (SN 2018dvf), ZTF18aawpcel (SN 2018cir), and ZTF18abddmrf (SN 2018dsx).

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