Spectroscopic Classification of SN 2017coa as a Type Ia Supernova
Danfeng Xiang, Liming Rui, Xiaofeng Wang (Tsinghua Unviersity), Hanjie Tan(Chinese Culture University), Wenxiong Li (Tsinghua University),Tianmeng Zhang (NAOC), Zhijian Xu, Zesheng Yang, Hao Song, Jun Mo, Yuanhao Wang, Ziheng Zhou (Tsinghua University), Xianmin Meng, Shenban Qian (YNAO), Junjun Jia, Xu Zhou (NAOC), and Jujia Zhang (YNAO)
We obtained an optical spectrum (range 360-840 nm) of SN 2017coa,discovered by Tsinghua-NAOC Transient Survey (TNTS), on UT Mar.31.49 2017 with the 2.16-m telescope (+BFOSC) at Xinglong Station of National Astronomical Observatories of China (NAOC). The spectrum is consistent with that of a type Ia supernovae at about one week before the 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 2003kf at t=-9 days from the maximum light. After correcting for a redshift of 0.045 (from the SNID fit) for its host galaxy SDSS J084955.19+560554.6, an expansion velocity of about 12700 km/s can be derived from the absorption minimum of Si II 635.5 line. The classification spectrum is also posted on the IAU Transient Name Sever: http://wis-tns.weizmann.ac.il/object/2017coa/
optical,supernovae,transient