Spectroscopic Classifications of Optical Transients with the Keck I telescope

ATel #12279; J. S. Brown, R. J. Foley (UCSC)
on 9 Dec 2018; 06:59 UT
Distributed as an Instant Email Notice Supernovae
Credential Certification: Ryan Foley (foley@ucsc.edu)

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We report the following classifications of optical transients from spectroscopic observations with the LRIS spectrograph on the Keck I telescope. Targets were supplied by ZTF. All observations were made on 2018 Dec 8 UT. Classifications were performed with SNID (Blondin & Tonry, 2007, ApJ, 666, 1024).

 
Name         | IAU Name  | RA (J2000)  | Dec (J2000)  |   z   | Type | Phase  | Notes
 
ZTF18acqwdla | AT2018iuq | 07:05:53.44 | +12:53:34.69 | 0.028 |  II  |   --   | (1)   
ZTF18acqxcga | AT2018izd | 07:02:54.63 | +33:50:15.37 | 0.03  |  Ia  |  +2 d  | (2)  

Notes: When the redshift is given to 2 decimal places, it is derived from the SN spectrum. Otherwise, the redshift is determined from the host galaxy. (1) The spectrum has some similarities to SNe IIb at early phases. There is a strong absorption feature at ~6150 A, which could be Si II or high-velocity H alpha. If the latter, it corresponds to a velocity of -19,000 km/s. (2) Good match to a normal SN Ia near peak. The SN has a faint host galaxy with r_PS1 = 21.7 mag. At z = 0.03, this corresponds to a stellar mass of ~10^7 M_sun, making it one of the least-massive SN Ia host galaxies yet (see e.g., Brown et al., arxiv:1810.00011).