Spectroscopic follow-up observations of AT 2016coi (ASASSN-16fp) : possible detection of helium
ATel #9124; M. Yamanaka (Konan Univ.), T. Nakaoka, M. Kawabata, K. S. Kawabata (Hiroshima Univ.), M. Tanaka (NAOJ), N. Tominaga (Konan Univ.), K. Maeda (Kyoto Univ.), O. Hashimoto (Gunma Astronomical Observatory), K. Kinugasa (NAOJ), M. Takayama, and K. Morihana (Univ. of Hyogo) on the behalf of the OISTER collaboration
on 7 Jun 2016; 16:59 UT
Credential Certification: Masayuki Yamanaka (yamanaka@center.konan-u.ac.jp)
Subjects: Optical, Supernovae
We report the optical low-resolution spectroscopic observations
of supernova AT 2016coi (ATEL #9086), which is classified as
broad-lined Type Ic supernova (SN) by the previous report (ATEL #9090).
Our observations have been performed using Hiroshima One-shot
Wide-field Polarimeter (HOWPol; Kawabata et al. 2008) attached
to the 1.5-m Kanata telescope, Gunma Low-resolution Spectrograph
(GLOWS) attached to the Gunma 1.5-m telescope, and Medium And
Low-dispersion Long-slit Spectrograph (MALLS) attached to the 2.0-m
Nayuta telescope in the framework on the Optical and Infrared
Synergetic Telescopes for Education and Research (OISTER)
observation program on May 31, Jun 1 and Jun 2. We confirmed that
the spectra exhibit the high-velocity features of Si II and Ca II IR triplet.
In addition to these features, the absorption lines at 5550 A, 6300 A,
and 6700 A were detected. These can be possibly attributed to He
I 5876, 6678, and 7065 lines with the velocity of 18,000 km/s.
If these identifications are the case,
it implies the presence of helium in the ejecta of AT 2016coi.
