Spectroscopic classification of AT2020aavb as SN Ia and AT2020ywx as SN IIn

ATel #14210; A. Reguitti (UNAB, INAF-OAPd), S. Benetti (INAF-OAPd), F. Briganti (ISSP), P. Ochner (UniPd, INAF-OAPd), P. Campaner (Ponte di Piave Observatory)
on 24 Nov 2020; 12:40 UT
Distributed as an Instant Email Notice Supernovae
Credential Certification: Stefano Benetti (stefano.benetti@inaf.it)

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In the framework of the Asiago Transient Classification Program (Tomasella et al. 2014, AN, 335, 841) we report the spectroscopic classification of AT2020aavb (Briganti 2020; TNSTR 3539) in NGC 3697, and AT2020ywx (ATLAS20bewg; Srivastav et al. 2020, TNSAN 215) in the galaxy WISEA J115326.45+105347.2. The candidates were provided by the Italian Supernovae Search Project (ISSP, http://italiansupernovae.org/en.html ) and the ATLAS survey (Tonry et al. 2018, PASP, 130, 4505), respectively.

The observations were performed with the Asiago 1.82 m Copernico Telescope equipped with AFOSC (range 340-820 nm; resolution 1.4 nm) on 2020-11-24.2.

 
IAU Name   | Survey name | Redshift | Discovery (UT)| Discovery mag        | Type | Phase     | Notes 
AT2020aavb | AT2020aavb  | 0.0211   | 2020-11-23.12 | 17.0 (Clear)         | Ia   | -1 week   | (1) 
AT2020ywx  | ATLAS20bewg | 0.021    | 2020-11-04.62 | 16.48 (ATLAS-orange) | IIn  | 1.5 month | (2) 

(1) We confirm the classification as a SN Ia reported by Balcon 2020 (TNSCR 8052). Gelato (Harutyunyan et al. 2008, A&A, 488, 383) returns a fair match with the spectrum of the type Ia SN 1998bu (Jha et al. 1999, ApJS, 125, 73; Spyromilio et al. 2004, A&A, 426, 547) about one week before maximum. The redshift is from Hickson et al. 1992, ApJ, 399, 353.

(2) The spectrum shows a prominent narrow Halpha in emission on top of a much broader component, as in Type IIn SNe. By deconvolving the Halpha profile, we found the FWHM velocities of the two components to be 1300 km/s, corrected for the instrumental resolution, and 15000 km/s, respectively. We detect Hbeta in emission, together with [O III] 4959,5007 and [O II] 3726 contaminant lines. Faint He I 5876 and 7065 emission lines are also detected. Gelato (Harutyunyan et al. 2008, A&A, 488, 383) finds a match with the spectrum of the luminous type IIn SN 2010jl (Zhang et al. 2012, AJ, 144, 131) about 40 days after maximum. The redshift is determined from the host galaxy [O III] lines in the supernova spectrum.