Spectroscopic Classification of SN 2018nt as a Reddened Type Ia Supernova

ATel #11281; J. Vinko (Konkoly Observatory; U Szeged; UT Austin), J. C. Wheeler (UT Austin)
on 9 Feb 2018; 20:17 UT
Credential Certification: Jozsef Vinko (vinko@astro.as.utexas.edu)

Subjects: Optical, Supernovae

An optical spectrum (range 360-700 nm) of SN 2018nt (K2 C16-0043), was obtained with the "Low Resolution Spectrograph-2" (LRS2) on the 10m Hobby-Eberly Telescope at McDonald Observatory by S. Odewahn on 2018 Feb 05.20 UT.

The spectrum is consistent with that of a heavily reddened Type Ia supernova (with Av > 2 mag) about 3 weeks after maximum light. Cross-correlation with a library of supernova spectra using the "Supernova Identification" code (SNID; Blondin and Tonry 2007, Ap.J., 666, 1024) shows that it matches with SN 2004L at 20 days after maximum light.

The redshift, estimated from the broad SN features by SNID, is z ~ 0.038, which is consistent with that of the presumed host galaxy SDSS J092327.31+171103.5 of z = 0.035.

Our classification spectrum is posted on the IAU Transient Name Sever: http://wis-tns.weizmann.ac.il/object/2018nt/