Spectroscopic classification of AT 2022aawb as a Type-I superluminous supernova with NOT ALFOSC

ATel #15811; F. Poidevin, I. Perez-Fournon (IAC & ULL), Z. Delgado-Gonzalez (ULL), S. Geier (GRANTECAN & IAC), R. Clavero, C. Jimenez Angel (IAC & ULL), R. Konyves-Toth (Konkoly Observatory, Univ. of Szeged), R. Marques-Chaves (Univ. of Geneva), C. M. B. Omand (The Oskar Klein Centre), and R. Shirley (Univ. of Southampton) on behalf of the SGLF SLSN group
on 15 Dec 2022; 17:02 UT
Distributed as an Instant Email Notice Supernovae
Credential Certification: Ismael Perez-Fournon (ipf@iac.es)

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We report on the classification of AT 2022aawb (= ZTF22abvcnnl, PS22llz, ATLAS22bnhm) as a Type-I superluminous supernova (SLSN-I) using NOT ALFOSC and grism 4 on 2022-12-14 20:42:40.706. The spectrum shows clearly the W (OII absorption) feature, characteristic of SLSNe-I before maximum light, at a redshift of z ~ 0.13. It has been rising in flux for about 30 days since the first ZTF detection on MJD = 59898.223 (2022-11-15 05:20:42). The last ZTF detections have magnitudes g = 18.495 +/- 0.085 (on MJD = 59928.198, 2022-12-15 04:44:29) and r = 18.418 +/- 0.084 (on MJD = 59928.175, 2022-12-15 04:12:25). Taking into account the Galactic extinction (Ag = 0.42, Ar = 0.29; Schlafly et al. 2011), the last absolute magnitudes are Mg = -20.79, Mr = -20.74. The likely host galaxy is a faint, blue, resolved source detected in the DESI Legacy Imaging Surveys at < 0.2" from the SN position and magnitudes g = 22.99, r = 22.56, and z = 22.14. We encourage photometric and spectroscopic follow-up observations.

We thank Viktoria Pinter for help with the NOT ALFOSC observations.

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.

ZTF light curve: https://lasair-ztf.lsst.ac.uk/object/ZTF22abvcnnl/

DESI Legacy Imaging Surveys finding chart