Abstract
We present a detection in pre-explosion Hubble Space Telescope (HST) imaging of a point source consistent with being the progenitor star of the Type IIb supernova (SN IIb) 2016gkg. Post-explosion imaging from the Keck adaptive optics system was used to perform relative astrometry between the Keck and HST imaging. We identify a single point source in the HST images coincident with the SN position to 0.89σ. The HST photometry is consistent with the progenitor star being an A0 Ia star with T = 9500 K and log (L/L⊙) = 5.15. We find that the SN 2016gkg progenitor star appears more consistent with binary than single-star evolutionary models. In addition, early-time light-curve data from SN 2016gkg revealed a rapid rise in luminosity within ~0.4 d of non-detection limits, consistent with models of the cooling phase after shock break-out. We use these data to determine an explosion date of 2016 September 20.15 and progenitor-star radius of log (R/R⊙) = 2.41, which agrees with photometry from the progenitor star. Our findings are also consistent with detections of other SNe IIb progenitor stars, although more luminous and bluer than most other examples.
| Original language | English (US) |
|---|---|
| Pages (from-to) | 4650-4657 |
| Number of pages | 8 |
| Journal | Monthly Notices of the Royal Astronomical Society |
| Volume | 465 |
| Issue number | 4 |
| DOIs | |
| State | Published - Mar 11 2017 |
Funding
We would like to thank John Tonry for providing data from ATLAS, as well as Dan Kasen, Josiah Schwab, Enrico Ramirez-Ruiz, and Stan Woosley for their helpful discussions. We also thank Marc Kassis for his assistance with Keck data acquisition, Nathan Smith and Jennifer Andrews for discussing spectroscopy of SN 2016gkg, and Subo Dong and Ping Chen for assistance with Swift photometry of SN 2016gkg. TheUCSC group is supported in part by NSF grant AST-1518052 and from fellowships from the Alfred P. Sloan Foundation and the David and Lucile Packard Foundation to RJF. 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 NASA. The observatory was made possible by the generous financial support of theW. M. Keck Foundation. We wish to recognize and acknowledge the cultural significance that the summit of Mauna Kea has within the indigenous Hawaiian community. We are most fortunate to have the opportunity to conduct observations from this mountain. Some of our photometry of SN 2016gkg comes from All Sky Automated Survey for SuperNovae (ASAS-SN), the Asteroid Terrestrial-impact Last Alert System (ATLAS), Swift, and the Las Cumbres Observatory Global Telescope Network (LCOGT). The Hubble Space Telescope (HST) is operated by NASA/ESA. Some of our analysis is based on data obtained from the HST archive operated by STScI. Our analysis is based in part on observations obtained at the Southern Astrophysical Research (SOAR) telescope, which is a joint project of the Ministério da Ciência, Tecnologia, e Inovação (MCTI) da Reṕublica Federativa do Brasil, the US National Optical Astronomy Observatory (NOAO), the University of North Carolina at Chapel Hill (UNC), and Michigan State University (MSU). This work has made use of the following facilities: Keck (NIRC2); SOAR (Goodman).
Keywords
- Stars: evolution
- Supernovae: general
- Supernovae: individual: SN 2016gkg
ASJC Scopus subject areas
- Astronomy and Astrophysics
- Space and Planetary Science