SALT spectroscopic classification of ASASSN-17bu (= SN 2017yv) as a type-Ia supernova before maximum light
ATel #10048; S. W. Jha (Rutgers), M. Kotze (SALT/SAAO)
on 3 Feb 2017; 23:56 UT
Distributed as an Instant Email Notice Supernovae
Credential Certification: Saurabh Jha (firstname.lastname@example.org)
Subjects: Optical, Supernovae
We obtained SALT (+RSS) spectroscopy of ASASSN-17bu (= SN 2017yv; ATel
#10033) on 2017 Feb 3.9 UT, covering the wavelength range 350-940 nm.
Cross-correlation of the supernova spectrum with a template library using
SNID (Blondin & Tonry 2007, ApJ, 666, 1024) shows ASASSN-17bu is a type-Ia
supernova several days before maximum light. A good SNID match is obtained
with SN 1990O at -6 days. Adopting the redshift z=0.015584 for the host galaxy
ESO 375-G018 (from the 6dF Galaxy Survey, via NED; Jones et al. 2004, MNRAS,
355, 747; Jones et al. 2009, MNRAS, 399, 683), the expansion velocity for
ASASSN-17bu, measured to the trough of the Si II (rest 635.5 nm) line, is
12,700 km/s. The spectrum shows substantial narrow interstellar Na I D
absorption, both from the host galaxy (D1+D2 equivalent width approximately 2
Angstrom) and from the Milky Way (approximately 1 A), implying the supernova
may be reddened, despite a relatively blue spectral shape.
Our spectrum is posted on the
Transient Name Server SN 2017yv page.