Spectroscopic classification of SN 2018bsn as a type Ia supernova before the maximum
ATel #11651; Jujia Zhang, Kai Ye (YNAO); Zhijian Xu, Wenxiong Li, Xiaofeng Wang, Jun Mo (THU), Hanjie Tan(CCU) and Tianmeng Zhang (NAOC)
on 18 May 2018; 03:21 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 350-890 nm) of SN 2018bsn, discovered by the Tsinghua-NAOC Transient Survey (TNTS), on UT May 17.7 2018 with the 2.4 m telescope (LJT + YFOSC) at Lijiang Observatory of Yunnan Observatories (YNAO). The spectrum is consistent with a type Ia supernova at a few days before the maximum light. Cross-correlation with a library of supernova spectra using the "Supernova Identification" code (SNID; Blondin and Tonry 2007, ApJ, 666, 1024) shows that it matches with SN 1989B at t = -7 days
from the maximum light. After correcting for a redshift of 0.059 for its host galaxy 2MASX J14572815+0550375, an expansion velocity of about 14,000 km/s can be derived from the absorption minimum of Si II 635.5 nm. The classification spectrum is also posted on the IAU Transient Name Sever: https://wis-tns.weizmann.ac.il/object/2018bsn
