Spectroscopic Classification of DLT18i (=SN 2018yu) as a young Type Ia Supernova
ATel #11374; Jujia Zhang (YNAO) and Xiaofeng Wang (THU)
on 1 Mar 2018; 14:51 UT
Distributed as an Instant Email Notice Supernovae
Credential Certification: Ju-Jia Zhang (jujia@ynao.ac.cn)
Subjects: Optical, Supernovae
We obtained an optical spectrum (range 350-900 nm) of DLT18i (=SN 2018yu, ATEL#11371), discovered by the D<40 Mpc (DLT40) supernova search, on UT Mar. 1.51 2018 with the 2.4 m telescope (+YFOSC) at the LiJiang Observatory of YNAO. The spectrum is consistent with a young type-Ia supernova at a few days before the maximum. Cross-correlation with a library of supernova spectra using the GELATO (Harutyunyan et al. 2008, A.Ap. 488, 383; https://gelato.tng.iac.es) shows that 2018yu matches with SN 2003kf at 8 days before maximum light. Adopting for the host galaxy (NGC 1888) a recession velocity of 2432 km/s, we measure the velocity of the Si II 635.5-nm absorption feature to be about 15000 km/s, and the velocity of Ca II H&K and NIR triplet absorptions to be about 24000 km/s. A notch at the redder winger of Si II 6355 might be contributed to the absorption of CII 6580 at a velocity about 14000 km/s. However, it is not certain for the detection of C II 6580 due to the low signal noise ratio at this region.
The classification spectrum is also posted on the IAU Transient Name Sever: https://wis-tns.weizmann.ac.il/object/2018yu.
