Classification certificate for object 2018gv
TNS Classification Report No. 1643 [ 2018TNSCR..75....1S ]

Date Received (UTC): 2018-01-16 12:41:15
Sender: Matthew Siebert
Group: None

M. R. Siebert, G. Dimitriadis, R. J. Foley (UCSC) report/s a classification of object: SN 2018gv

Type: SN Ia
Redshift: 0.005274

Remarks: The spectrum indicates that SN 2018gv is a very young, normal Type Ia supernova. Using SNID (Blondin & Tonry, 2007, ApJ, 666, 1024), we find a good match to several Type Ia SNe 10-15 days before maximum brightness. We note that the small number of SNe Ia observed at very early phases often results in a bias to later phases. The SN was discovered at 16.5 mag, which assuming a distance modulus of 31.1 mag for the host galaxy NGC 2525 (Tully et al., 2013, AJ, 146, 86T), corresponds to an absolute magnitude of -14.8 -- or at least 4 mag below peak brightness. This further indicates that the SN is particularly young. If the SN has minimal host reddening, it will peak at V ~ 12 mag. We measure an Si II 6355 velocity of -16,800 km/s. Similarly, we measure a C II 6580 velocity of -15,300 km/s. We detect narrow Ca H&K absorption at the host-galaxy redshift, but do not detect narrow Na D.

The following Classification spectrum was provided:

Obsdate: 2018-01-16 09:20:20
Instrument: LRIS
Telescope: Keck I 10m

Details of the object and its spectra can be viewed here: https://wis-tns.weizmann.ac.il/object/2018gv