We report the transformation of the SN IIb 2020jfv to an SN IIn. SN 2020jfv (https://www.wis-tns.org/object/2020jfv) was discovered with the Asteroid Terrestrial-impact Last Alert System (ATLAS) at a difference magnitude in orange-ATLAS of 17.768 on 2020-05-05T14:22:33.6 (https://www.wis-tns.org/object/2020jfv/discovery-cert). Its host galaxy is SDSS J230635.98+003641.5/WISEA J230635.97+003641.9, which has a redshift of z~0.016389 reported in SIMBAD. A public classification of IIb and a redshift of z=0.01709 was reported from a spectrum obtained with SEDM on the Palomar 1.5m telescope on 2020-06-20T10:36:21 UTC (https://www.wis-tns.org/object/2020jfv/classification-cert), in which broad Balmer and He I emission features are visible. A spectrum obtained with the Binospec spectrograph mounted on the MMT on 2024-12-05T04:04:36 UTC, 1675 days after discovery in the observer frame, indicates line-dominated emission and prominent narrow Balmer features (Halpha width <=2000 km/s, blended with host emission; see attached plot). Photometry of 2020jfv was most recently reported at a ZTF-r band difference magnitude of 20.021+-0.203 on 2024-12-03T03:47:31. Follow-up observations of the event's most recent interaction phase are encouraged.
Transient vetting was done using the YSE-PZ transient management platform. YSE-PZ was developed by the UC Santa Cruz Transients Team. The UCSC team is supported in part by NASA grants NNG17PX03C, 80NSSC19K1386, and 80NSSC20K0953; NSF grants AST-1518052, AST-1815935, and AST-1911206; the Gordon & Betty Moore Foundation; the Heising-Simons Foundation; a fellowship from the David and Lucile Packard Foundation to R. J. Foley; Gordon and Betty Moore Foundation postdoctoral fellowships and a NASA Einstein fellowship, as administered through the NASA Hubble Fellowship program and grant HST-HF2-51462.001, to D. O. Jones; and a National Science Foundation Graduate Research Fellowship, administered through grant No. DGE-1339067, to D. A. Coulter.
This report is based on observations obtained with the Samuel Oschin 48-inch Telescope and the 60-inch Telescope at the Palomar Observatory as part of the Zwicky Transient Facility project.
This report has also made use of data from the Asteroid Terrestrial-impact Last Alert System (ATLAS) project. The Asteroid Terrestrial-impact Last Alert System (ATLAS) project is primarily funded to search for near earth asteroids through NASA grants NN12AR55G, 80NSSC18K0284, and 80NSSC18K1575; byproducts of the NEO search include images and catalogs from the survey area. This work was partially funded by Kepler/K2 grant J1944/80NSSC19K0112 and HST GO-15889, and STFC grants ST/T000198/1 and ST/S006109/1. The ATLAS science products have been made possible through the contributions of the University of Hawaii Institute for Astronomy, the Queen’s University Belfast, the Space Telescope Science Institute, the South African Astronomical Observatory, and The Millennium Institute of Astrophysics (MAS), Chile.
| Catalog | Name | Reported RA | Reported DEC | Reported Obj-Type | Reported Redshift | Host Name | Host Redshift | Remarks | TNS RA | TNS DEC | TNS Obj-Type | TNS Redshift |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| TNS | 2020jfv | 23:06:35.750 | +00:36:43.60 | SN IIb | 0.01709 | 23:06:35.750 | +00:36:43.60 | SN IIb | 0.01709 |
Comments
Interesting. This supernova
Interesting. This supernova and transition was also discussed in A&A 655, A105 (2021).
https://www.aanda.org/articles/aa/full_html/2021/11/aa41374-21/aa41374-…
from Abstract "SN 2020jfv has a poorly constrained early-time LC, but it is of interest because of the transition from a hydrogen-poor Type IIb to a Type IIn, where the nebular spectrum after the light-curve rebrightening is dominated by Hα, although with an intermediate line width. "