Discovery and Follow-up Observations of the Young Type Ia Supernova 2016coj Academic Article uri icon


  • 2017. The American Astronomical Society. All rights reserved. The Type Ia supernova (SN Ia) 2016coj in NGC 4125 (redshift z = 0.00452 0.00006) was discovered by the Lick Observatory Supernova Search 4.9 days after the fitted first-light time (FFLT; 11.1 days before B-band maximum). Our first detection (prediscovery) is merely 0.6 0.5 days after the FFLT, making SN 2016coj one of the earliest known detections of an SN Ia. A spectrum was taken only 3.7 hr after discovery (5.0 days after the FFLT) and classified as a normal SN Ia. We performed high-quality photometry, low- and high-resolution spectroscopy, and spectropolarimetry, finding that SN 2016coj is a spectroscopically normal SN Ia, but the velocity of Si ii 6355 around peak brightness (12,600 kms-1) is a bit higher than that of typical normal SNe. The Si ii 6355 velocity evolution can be well fit by a broken-power-law function for up to a month after the FFLT. SN 2016coj has a normal peak luminosity (MB -18.9 0.2 mag), and it reaches a B-band maximum 16.0 days after the FFLT. We estimate there to be low host-galaxy extinction based on the absence of Na i D absorption lines in our low- and high-resolution spectra. The spectropolarimetric data exhibit weak polarization in the continuum, but the Si ii line polarization is quite strong (0.9% 0.1%) at peak brightness.

published proceedings


altmetric score

  • 111.5

author list (cited authors)

  • Zheng, W., Filippenko, A. V., Mauerhan, J., Graham, M. L., Yuk, H., Hosseinzadeh, G., ... Wang, X.

citation count

  • 15

complete list of authors

  • Zheng, WeiKang||Filippenko, Alexei V||Mauerhan, Jon||Graham, Melissa L||Yuk, Heechan||Hosseinzadeh, Griffin||Silverman, Jeffrey M||Rui, Liming||Arbour, Ron||Foley, Ryan J||Abolfathi, Bela||Abramson, Louis E||Arcavi, Iair||Barth, Aaron J||Bennert, Vardha N||Brandel, Andrew P||Cooper, Michael C||Cosens, Maren||Fillingham, Sean P||Fulton, Benjamin J||Halevi, Goni||Howell, D Andrew||Hsyu, Tiffany||Kelly, L||Kumar, Sahana||Li, Linyi||Li, Wenxiong||Malkan, Matthew A||Manzano-King, Christina||McCully, Curtis||Nugent, Peter E||Pan, Yen-Chen||Pei, Liuyi||Scott, Bryan||Sexton, Remington Oliver||Shivvers, Isaac||Stahl, Benjamin||Treu, Tommaso||Valenti, Stefano||Vogler, H Alexander||Walsh, Jonelle L||Wang, Xiaofeng

publication date

  • January 2017