Spectrocopic Classifcation of SN 2017gtd As a Type II Supernova
ATel #10755; Danfeng Xiang, Liming Rui, Han Lin, Xiaofeng Wang (Tsinghua University), Yong Zhao, Huijuan Wang, Tianmeng Zhang (NAOC), and Jujia Zhang (YNAO)
on 18 Sep 2017; 06:41 UT
Distributed as an Instant Email Notice Supernovae
Credential Certification: Xiaofeng Wang (wang_xf@mail.tsinghua.edu.cn)
Subjects: Optical, Supernovae, Transient
We obtained an optical spectrum (range 370-870 nm) of SN 2017gtd, discovered by Jaroslaw Grzegorzek, on UT Sept.17.80 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 II supernova before the peak brightness. 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 1999gi at t=-4 days from the maximum light. After correcting for a redshift of 0.0170 for its host galaxy IC 221, an expansion velocity of about 11000 km/s can be derived from the absorption minimum of Ha 656.3nm line. Our classification spectrum is also posted on the IAU Transient Name Sever: http://wis-tns.weizmann.ac.il/object/2017gtd/
