Spectroscopic Classification of two ASAS-SN Supernovae with MDM
ATel #11837; Subhash Bose, Subo Dong, P. Chen (KIAA-PKU), Jose L. Prieto (UDP), J. Rupert (MDM Observatory), K. Z. Stanek (OSU)
on 10 Jul 2018; 16:34 UT
Credential Certification: Subhash Bose (bose@pku.edu.cn)
Subjects: Optical, Supernovae
We report optical spectroscopic observation of supernova candidates ASASSN-18ll/2018cdh (ATel #11686) and ASASSN-18od/2018dda (ATel #11832) using OSMOS (range 398-686 nm) mounted on the MDM 2.4m telescope at KPNO. Both targets were discovered by the All-Sky Automated Survey for Supernovae (ASAS-SN, Shappee et al. 2014).
ASASSN-18ll was observed on 2018-06-17.28 and 2018-07-06.23 with MDM/OSMOS. The spectrum on 2018-06-17.28 shows narrow P-Cygni profiles of HeI (velocity ~1100 km/s) without any presence of broad emission features. This is consistent with several SNe Ibn (e.g. SN 2010al and PTF12ldy) near maximum. The later spectrum obtained on 2018-07-06.23 does not show any prominent P-Cygni profiles, but only weak emission line of HeI, which is also consistent with Type Ibn SN PTF12ldy (Hosseinzadeh et al. 2016), around a month after the maximum light.
ASASSN-18od, observed on 2018-07-06.42, is a type Ia SN a week before the maximum. The age has been estimated using SNID (Blondin & Tonry, 2007, ApJ, 666, 1024) and the redshift is consistent with that of the host galaxy (z=0.018229).
