Liverpool Telescope classification of ATLAS16bdg as a Type Ia supernova near maximum light
ATel #9165; C. G. Mundell (U. Bath), R. J. Smith (LJMU), M. J. Childress (U. Southampton)
on 17 Jun 2016; 19:53 UT
Distributed as an Instant Email Notice Supernovae
Credential Certification: Michael Childress (mjc@mso.anu.edu.au)
Subjects: Optical, Supernovae
On 2016 June 15 at approximately 21:03 UT, we performed multicolour optical imaging, spectroscopy and polarimetry with the 2-m robotic Liverpool Telescope IO:O camera of galaxy NGC4708 in which a bright optical transient was reported by Tonry et al. ATel #9151 (ATLAS16bdg).
A bright optical source offset from the center of the bulge by approximately 2.2 arc sec is confirmed in our images taken with the IO:O camera at coordinates: RA, Dec (J2000) = 12:49:41.374 -11:05:34.42.
Follow-up spectroscopy with the Liverpool Telescope SPRAT spectrograph of this source on 2016 June 16 shows a strong and broad Si II 6355 feature, as well as a weak sulphur "W" and iron absorption features blueward of 5000 AA, all consistent with this transient being a Type Ia supernova. We confirmed this classification with SNID (Blondin & Tonry, 2007, ApJ, 666, 1024), which shows good matches to SN 2001ay at phase +3 days or SN 2003W at phase -4 days, both at a redshift consistent with that of the host galaxy NGC 4708 (z=0.013896, via NED).
Further analysis of multi-colour optical imaging, spectroscopy and polarimetry is in progress. Radio observations with the eMERLIN interferometer are scheduled.
