Spectroscopic Classification of ASASSN-16aj (AT 2016K) as a Type Ia Supernova.

We report an optical spectrum (range 350-900 nm) of ASASSN-16aj (ATEL #8542, AT 2016K) obtained on UT 2016 Jan. 15.5 with the 2.4 m telescope (LJT + YFOSC) at Lijiang observatory of Yunnan Observatories. The spectrum is consistent with a Type Ia supernova at around 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 2003du at t = -1 days. Adopting a redshift of 0.0307 for its host galaxy NGC 1562, an expansion velocity of about 11,500 km/s can be derived from the absorption minimum of Si II 635.5 nm.