Spectroscopic Classification of SN 2018agk with SOAR/Goodman
ATel #11433; K. C. Dage, S. E. Zepf, J. Strader (MSU), G. Dimitriadis, R. J. Foley, C. D. Kilpatrick, D. O. Jones, C. Rojas-Bravo (UCSC)
on 16 Mar 2018; 15:39 UT
Distributed as an Instant Email Notice Supernovae
Credential Certification: Ryan Foley (foley@ucsc.edu)
Subjects: Optical, Supernovae
Referred to by ATel #: 11551
We obtained spectroscopic observations of SN 2018agk with the Goodman spectrograph on the 4-m SOAR telescope on 2018 Mar 16 UT. The spectrum indicates that SN 2018agk is a young Type Ia supernova. Using SNID (Blondin & Tonry, 2007, ApJ, 666, 1024), we find a good match to several Type Ia SNe 3-10 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 20.2 mag, which assuming a distance modulus of 35.3 mag for the host galaxy IC 855 (based on its redshift), corresponds to an absolute magnitude of -15.2 -- or ~4 mag below peak brightness. We measure an Si II 6355 velocity of -11,200 km/s. We detect a possible C II 6580 feature (an additional indication of a young age) with a velocity of -11,300 km/s.
