Spectroscopic classification of SN 2021aai as a young Type II SN
ATel #14326; A. Reguitti (UNAB), A. Pastorello, G. Valerin (INAF-OAPd)
on 18 Jan 2021; 11:53 UT
Distributed as an Instant Email Notice Supernovae
Credential Certification: Andrea Pastorello (andrea.pastorello@oapd.inaf.it)
Subjects: Optical, Supernovae, Transient
We report the spectroscopic classification of SN 2021aai (ZTF21aadoizf; Munoz-Arancibia et al. 2021, TNSTR, 112, 1) in the spiral galaxy NGC 2268, in the framework of the Nordic Optical Telescope (NOT) Unbiased Transient Survey 2 (NUTS2; ATel #8992, http://nuts.sn.ie ). The candidate was discovered by the Zwicky Transient Factory (ZTF; Bellm et al. 2019, Graham et al. 2019).
The observation was performed with the 2.56 m Nordic Optical Telescope equipped with ALFOSC (range 340-980 nm; resolution 1.4 nm), on 2021-01-17.89 (UT).
IAU Name | Survey name | Redshift | Discovery (UT) | Discovery mag | Type | Phase | Note
SN 2021aai | ZTF21aadoizf | 0.007428 | 2021-01-12.60 | 18.75 (g-ZTF) | II | 1 week | (1)
(1) The spectrum is that of a Type II SN about one week after the explosion, in agreement with the classification of Dahiwale et al. 2021, TNSCR, 8586, 1. The spectrum shows prominent Balmer lines and a weak He I 5876, with P Cygni profiles. From the position of the Halpha minimum, we infer an expansion velocity of the ejecta of about 6700 km/s. The faint absolute magnitude (M_r ~ -14.5 mag) suggests that SN 2021aai is a low-luminosity SN IIP (Pastorello et al. 2004, MNRAS, 347, 74; Spiro et al. 2014, MNRAS, 439, 2873). The redshift for the host galaxy is taken from Springob et al. 2005, ApJS, 160, 149.
