Is supernova SN 2020faa an iPTF14hls look-alike?

Abstract

Context. We present observations of ZTF20aatqesi (SN 2020faa). This Type II supernova (SN) displays a luminous light curve (LC) that started to rebrighten from an initial decline. We investigate this in relation to the famous SN iPTF14hls, which received a great deal of attention and multiple interpretations in the literature, but whose nature and source of energy still remain unknown. Aims. We demonstrate the great similarity between SN 2020faa and iPTF14hls during the first 6 months, and use this comparison to forecast the evolution of SN 2020faa and to reflect on the less well observed early evolution of iPTF14hls. Methods. We present and analyse our observational data, consisting mainly of optical LCs from the Zwicky Transient Facility in the gri bands and of a sequence of optical spectra. We construct colour curves and a bolometric lc, and we compare ejecta-velocity and black-body radius evolutions for the two supernovae (SNe) and for more typical Type II SNe. Results. The LCs show a great similarity with those of iPTF14hls over the first 6 months in luminosity, timescale, and colour. In addition, the spectral evolution of SN 2020faa is that of a Type II SN, although it probes earlier epochs than those available for iPTF14hls. Conclusions. The similar LC behaviour is suggestive of SN 2020faa being a new iPTF14hls. We present these observations now to advocate follow-up observations, since most of the more striking evolution of SN iPTF14hls came later, with LC undulations and a spectacular longevity. On the other hand, for SN 2020faa we have better constraints on the explosion epoch than we had for iPTF14hls, and we have been able to spectroscopically monitor it from earlier phases than was done for the more famous sibling.

A common envelope jets supernova (CEJSN) impostor scenario for fast blue optical transients

“…Thöne et al (2011) explain the unusual gamma-ray burst GRB 101225A by a NS that merged with a helium star. The enigmatic supernovae iPTF14hls (Arcavi et al 2017) and SN 2020faa (Yang et al 2021) might be CEJSN events (Soker & Gilkis 2018).…”

Optical Rebrightening of Extragalactic Transients from the Zwicky Transient Facility

“…4) and Hα and Hβ in particular appear to develop double peaks, pointing to the SN ejecta interacting with CSM having a disk-like geometry (Leonard et al 2000). Its light curve, particularly the luminous peak combined with the broad shape, bears a striking resemblance to that of the peculiar iPTF14hls (Arcavi et al 2017) and SN 2020faa (Yang et al 2021). Continued followup observations of this event will be able to provide further constraints.…”

Three-dimensional simulations of the jet feedback mechanism in common envelope jets supernova

“…Soker & Gilkis (2018) proposed that the enigmatic supernova iPTF14hls (Arcavi et al 2017) was a CEJSN event. The CEJSN might account also for SN 2020faa that is a similar supernova to iPTF14hls (see Yang et al 2021 for the observations of SN 2020faa). Soker et al (2019) proposed the CE-JSN scenario for the fast-rising blue optical transient AT2018cow.…”