Spectroscopic Classification of AT 2020scq with Faulkes-North and Keck I
ATel #14022; R. J. Foley, G. Dimitriadis, D. O. Jones, M. R. Siebert, K. Taggart, S. Tinyanont (UC Santa Cruz), M. R. Drout (U Toronto), W. V. Jacobson-Galan, C. D. Kilpatrick, R. Margutti, G. Terreran (Northwestern), A. Rest (STScI), S. Smartt (QUB), on behalf of the Young Supernova Experiment
on 17 Sep 2020; 16:28 UT
Distributed as an Instant Email Notice Supernovae
Credential Certification: Ryan Foley (foley@ucsc.edu)
Subjects: Optical, Supernovae, Transient
We report the classification of AT 2020scq from spectroscopic observations with the FLOYDS spectrograph on Faulkes-North telescope, made on 2020 Sep 3 UT, and LRIS on the Keck I telescope, made on 2020 Sep 17. The target was discovered by ATLAS and is also being observed by the Young Supernova Experiment (YSE).
The first spectrum has a blue continuum with strong narrow H-alpha emission at the redshift of its host galaxy (z = 0.030). The narrow emission has a FWHM < 600 km/s, the resolution of the spectrum, but there is also possibly somewhat broader emission with a FWHM of 3500 km/s and a potential narrow absorption corresponding to H-alpha blueshifted by -2300 km/s. The second spectrum has broad P-Cygni profiles with H-alpha having a blueshifted absorption of -4100 km/s. The spectral features also have a narrow P-Cygni component, with H beta having a narrow absorption at -400 km/s.
Examining pre-discovery YSE photometry, we see that AT 2020scq had an outburst lasting approximately 30 days that peaked approximately on 59064 MJD, corresponding to ~25 days before discovery and ~27 days before peak.
We therefore classify AT 2020scq as a SN II similar to SN 2009ip (e.g., Mauerhan et al., 2013, MNRAS, 430, 1801; Pastorello et al., 2013, ApJ, 767, 1; Margutti et al., 2014, ApJ, 780, 21) where there was an outburst immediately proceeding the final explosion and then interaction with the recently expelled circumstellar medium.
