Spectroscopic Classifications of Optical Transients with Lick Shane + Kast

ATel #14479; T. Hung, S. Tinyanont, G. Dimitriadis, R. J. Foley (UCSC)
on 22 Mar 2021; 15:56 UT
Distributed as an Instant Email Notice Supernovae
Credential Certification: Samaporn Tinyanont (st@astro.caltech.edu)

Tweet

We report the classification of the optical transients from spectroscopic observations with the Kast spectrograph on the Shane telescope, made on 2021 Mar 22 UT. The targets were supplied by ATLAS and ZTF. The classifications were performed with SNID (Blondin & Tonry, 2007, ApJ, 666, 1024).

 
Name         |  IAU Name  | RA (J2000)  |  Dec (J2000) | z      | Type    | Phase | Notes
 
ATLAS21ikd   | AT2021gel | 12:26:32.288 | +31:25:42.22 | 0.06   | Ia-91bg | peak  | (1) 
ZTF21aaqhhfu | AT2021gno | 12:12:10.294 | +13:14:57.03 | 0.006  | II      | early | (2)  
ZTF21aapyiku | AT2021gtp | 08:48:50.270 | +29:52:13.94 | 0.0202 | Ia      | -14   | (3) 

Notes: When the redshift is given to 2 significant figures, it is derived from the SN spectrum. Otherwise, the redshift is determined from the host galaxy. (1) We measure a Si II 6355 velocity of -9,900 km/s. (2) The continuum is well fit by a black body with T = 12,000 K. We identify He I 5576 and H alpha with P-Cygni profiles in the continuum-subtracted spectrum. The velocity for both lines is -12,000 km/s. We note that AstroNote 2021-93 reported that AT2021gno has a blue featureless continuum on 2021-03-20 UT. (3) We measure a Si II 6355 velocity of -17,000 km/s.