Spectroscopic classification of SN 2018bwq as a type Ia supernova a few days before maximum light.
ATel #11667; Angel R. Lopez-Sanchez (AAO/Macquarie U.), Lluis Galbany (U. Pittsburgh), Yago Ascasibar (UAM), Kristin Fiegert (AAO), Leigh Burchat, Barb Long, Hayden Roberts, Pip Newling (Citizen scientists, Zooniverse), Rebecca J. Smethurst (U. Nottingham), Chris Lintott (U. Oxford), Anais Moller, Brad Tucker, Patrick Armstrong, Charles Bray, Seo-Won Chang, Chris Onken, Ryan Ridden-Harper, Georgie Taylor (ANU), Ashley Ruiter (UNSW Canberra), Brian Cox (U. Manchester), Julia Zemiro (Australian Broadcasting Corporation)
on 23 May 2018; 09:08 UT
Distributed as an Instant Email Notice Supernovae
Credential Certification: Lluis Galbany (lluisgalbany@gmail.com)
Subjects: Optical, Supernovae
We report the spectroscopic classification of SN 2018bwq (RA=21:29:11.76, DEC=-29:09:46.2) in the galaxy 2MASX J21291210-2909468. The candidate was discovered by the SkyMapper Transient (SMT) survey (Scalzo et al. 2017, PASA, 34:30) on UT 2018-05-13 15:34 UT at ~19.32 mag in the r-band. SMT utilizes the 268-Mpix camera on the SkyMapper 1.3-m telescope at Siding Spring Observatory near Coonabarabran, NSW, Australia (Keller et al., 2007, PASA, 24, 1). The object was photometrically discovered by citizen scientists as part of the Zooniverse Supernova Sighting Project.
Observations were performed on the 3.9m Anglo-Australian Telescope at Siding Spring Observatory on 2018-05-22 16:29 UT, using KOALA+AAOmega and grisms 580V+385R (3700-5700A and 6100-9300A). Classification was done with SNID (Blondin & Tonry, 2007, ApJ, 666, 1024), and the spectrum is available at the IAU Transient Name Server (see https://wis-tns.weizmann.ac.il/). The spectrum shows the Si II 6355A absorption, and MgII, and FeII absorption features characteristic of type Ia supernovae (SNe Ia). SNID gives a reasonable fit to all its main spectral features with spectra of normal and 91T-like SNe Ia a few days before peak brightness placed at redshift ~0.08, consistently with that of the host galaxy (0.084). We measure a Si II 6355 velocity of -9,500 km/s.
Survey Name | IAU Name | RA (J2000) | Dec (J2000) | Disc. Date | Source | Disc Mag | z | Type | Phase | Notes
SMT18iy | AT2018bwq | 21:29:11.76 | -29:09:46.2 | 20180513 | SkyMapper | 19.32r | 0.084 | Ia | pre-max | (1,2,3)
(1) Best SNID fit to SN2006le at -5 days. Redshift from host galaxy emission lines (Ha, Hb, [O III] 5007).
(2) Identified as a Supernova Candidate through a project run by the Zooniverse as part of the ABC Stargazing Live show (http://supernovasighting.org).
(3) Was identified by Zooniverse volunteers Leigh Burchat, Barb Long, Hayden Roberts, and Pip Newling.
