Spectroscopic Classification of SN 2018aqm as A Type Ia Supernova

ATel #11531; Han Lin, Xiaofeng Wang, Zhitong Li, Wenxiong Li, Danfeng Xiang, Liming Rui (THU), Zhijian Xu, Hanjie Tan (CCU), Huijuan Wang, Junjun Jia, Tianmeng Zhang (NAOC), Jujia Zhang(YNAO), and Jun Mo (THU)
on 12 Apr 2018; 08:12 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 385-855 nm) of SN 2018aqm, discovered by the Tsinghua-NAOC Transient Survey (TNTS), on UT Apr.10.82 2018 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 supernova a few days after the maximum light. Cross-correlation with a library of supernova spectra using the comparison tool SNID (Blondin & Tonry, 2007, ApJ, 666, 1024) shows that it matches with SN 2003cg at t=+5 days from the maximum light. The prominent Na I D absorption can be seen in the spectrum, with an equivalent width of about 1.7 Angstrom, indicates that the supernova sufferred significant reddening from its host galaxy. Given a redshift of 0.0324 for its host galaxy 2MFGC 13255, an expansion velocity of about 10600 km/s can be deduced from the Si II 635.5 absorption minimum. Our classification spectrum is also posted on the IAU Transient Name Sever: https://wis-tns.weizmann.ac.il/object/2018aqm