Spectroscopic Classification of Gaia18beg/SN 2018bgv as a Low-z SLSN-I by NUTS (NOT Un-biased Transient Survey)
ATel #11654; Subo Dong, S. Bose (KIAA-PKU), Lauri Siltala (NOT), Simon Holmbo, M. Stritzinger (Aarhus U), K. Z. Stanek (OSU), David Bersier (Liverpool), Michael Tucker, B. J. Shappee, M. Huber (Hawaii), Morgan Fraser (UCD) on behalf of the NUTS collaboration and the ASAS-SN and SCAT teams
on 19 May 2018; 01:20 UT
Distributed as an Instant Email Notice Supernovae
Credential Certification: Subo Dong (dongsubo@pku.edu.cn)
Subjects: Optical, Supernovae
The Nordic Optical Telescope (NOT) Unbiased Transient Survey (NUTS; ATel #8992) reports the spectroscopic classification of Gaia18beg/SN 2018bgv (RA: 11:02:30.29 Dec: +55:35:55.79) in host galaxy SDSS J110230.41+553555.1. The candidate was discovered by the Gaia Science Alerts project on UT 2018-05-06 17:19:40 at 18.3 mag. It was recovered on images taken by the All-Sky Automated Survey for SuperNovae
(ASAS-SN: Shappee et al. 2014) on UT 2018-05-15 at ~17 mag.
The observations were performed with the 2.56 m Nordic Optical Telescope equipped with ALFOSC (range 350-950 nm; resolution 1.6 nm
FWHM).
Survey Name | IAU Name | Discovery (UT) | Discovery mag | Observation (UT) | Redshift | Type | Phase | Notes
Gaia18beg | SN 2018bgv | 2018-05-06.72 | 18.3 | 2018-05-17.97 | 0.08 | SLSN-I| Pre-/Near-Peak | (1)
(1) The NOT/ALFOSC spectrum shows the "W-shape" OII broad absorption features characteristic for a hydrogen-poor superluminous supernova (SLSN-I) . In particular, its main spectral features match well with the pre-peak spectra of SLSN-I Gaia17biu/SN 2017egm (Bose et al. 2018) placed roughly at z ~ 0.08. The redshift is consistent with that of a tentative narrow H-alpha line likely from the host galaxy. Its very blue continuum and the ASAS-SN light curve also suggest that it is pre- or near maximum. The absolute optical magnitude is about -20.7, which is consistent with a SLSN-I before or near the peak. A subsequent spectrum taken on 2018-05-18.38 by Spectral Classification of Astronomical Transients (SCAT) survey utilizing the SuperNova Integral Field Spectrograph (SNIFS) on the University of Hawaii 88-inch telescope is consistent with the NOT spectrum.
