Las Campanas spectroscopic classification of young optical transients

ATel #14218; Carlos Contreras (LCO), Emilio D. Hueichapan (U. de Chile), Regis Cartier (CTIO/NOIRLab), Hugo Rivera (LCO), Carla Fuentes (LCO) and Alberto Pasten (LCO)
on 25 Nov 2020; 21:41 UT
Distributed as an Instant Email Notice Supernovae
Credential Certification: Carlos Contreras (ccontreras@carnegiescience.edu)

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We report the spectroscopic classification of the following transients discovered by Zwicky Transient Facility (https://www.ztf.caltech.edu/; Kulkarni et al. 2018, ATel #11266) and by the All Sky Automated Survey for SuperNovae ASAS-SN (see Shappee et al. 2014, ApJ, 788, 48 and http://www.astronomy.ohio-state.edu/~assassin/index.shtml ). The observations were performed with the IMACS spectrograph mounted on Walter Baade 6.5-m Magellan telescope on Las Campanas Observatory. We used SNID (Blondin and Tonry, 2007, ApJ, 666, 1024) cross-correlation software to classify the SN candidates spectra. We found three of them to match typical type Ia features, while the other two are very young SNe of type Ia and II. For the latter two SNe SNID was not able to provide a good match and phase due to their young peculiar spectra.

 
Survey name  | IAU name   | RA (J2000) | Dec (J(2000) | Source  | UT spectrum |  z      | Type | Phase       | Notes 
ASASSN-20op  | SN2020aary | 03:21:29.9 | -61:46:11.9  | ASAS-SN |  Nov 23.29  | 0.026   | Ia   | at max      | (1,5) 
ZTF20actddoh | SN2020aatc | 02:48:16.4 | -10:15:07.4  | ZTF     |  Nov 24.24  | 0.01525 | Ia   | +2.6 d      | (2,4,6) 
ZTF20acrzwvx | SN2020aatb | 05:24:46.4 | -15:56:31.4  | ZTF     |  Nov 24.28  | 0.00995 | II   | +2.4 d      | (2,4) 
ZTF20actjbaf | SN2020aaul | 08:01:41.4 | -10:24:21.0  | ZTF     |  Nov 24.30  | 0.08    | Ia   | -7 to -4 d  | (3,5) 
ZTF20actiymd | SN2020aauk | 08:17:50.9 | -05:43:09.7  | ZTF     |  Nov 24.33  | 0.03943 | Ia   | -10 to -8 d | (2,5) 

 
(1) Redshift measured from host galaxy narrow emission lines. 
(2) Host galaxy redshift from NED. 
(3) Redshift obtained from SNID. 
(4) The phase is measured the rest-frame time relative to the estimated epoch of the explosion. We estimate the epoch of the explosion as the mid-point between the last non-detection and the first detection. 
(5) Phase relative to maximum light estimated using SNID. 
(6) The spectrum shows a very broad feature from 675.0 to 835.0 nm, possibly due to C II, O I and Ca II blended spectral features. We measure a velocity for the Si II 6355 feature of 22,200 km/s. Follow-up observations are encouraged.