AstroNote 2022-144

We report the observation of SN 2022myl (https://www.wis-tns.org/object/2022myl), classified as Type IIn by the Zwicky Transient Facility (https://www.wis-tns.org/object/2022myl/classification-cert).

The target was observed on July 12.06UT with ALFOSC@NOT (range 3600-9600 Å, resolution 20 Å). The spectrum shows a blue continuum with Balmer and  HeI 5878 lines in emission. All lines have a narrow unresolved component on top of a broader (~60 Å) one, confirming the classification as a type IIn. We use GELATO (Harutyunyan et al. 2008, A&A 488, 383) to match the spectrum to a sample of SNe and find good agreement with SN 2009ip about 2 days after maximum (event B of 2012, Pastorello et al. 2013, ApJ, 767, 1), adopting redshift z=0.037 as retrieved from NED and reddening E(B-V)=0.2 to match the continuum. The match with SN 2009ip is also consistent with the light curve evolution reported by ZTF, where the absolute peak magnitude of SN 2022yml (-17.8 ) is also similar to that of SN 2009ip-like object.

We also note that, as in SN 2009ip, the HαIHβ ratio is very low,  ~1.2, possibly indicative of high CSM density (Levesque et al. 2014, AJ, 147, 23).

Based on observations made with the Nordic Optical Telescope, owned in collaboration by the University of Turku and Aarhus University, and operated jointly by Aarhus University, the University of Turku and the University of Oslo, representing Denmark, Finland and Norway, the University of Iceland and Stockholm University at the Observatorio del Roque de los Muchachos, La Palma, Spain, of the Instituto de Astrofisica de Canarias.
The research leading to these results has received funding from the European Union Seventh Framework Programme (FP7/2013-2016) under grant agreement No. 312430 (OPTICON).