TITLE:   GCN CIRCULAR
NUMBER:  20897
SUBJECT: LIGO/Virgo G277583: P200/DBSP Classification of ATLAS Candidates
DATE:    17/03/17 21:46:12 GMT
FROM:    Mansi M. Kasliwal at Caltech  <mansi@astro.caltech.edu>

N. Blagorodnova, K. Burdge, S. M. Adams and M. M. Kasliwal (Caltech)

report on behalf of the GROWTH (Global Relay of Observatories Watching
Transients Happen) collaboration

On UT 2017-03-16, we spectroscopically classified the following ATLAS
optical transient candidates (LVC GCN#20881) using the Double Beam
Spectrograph (Oke & Gunn 1982) on the Palomar 200-inch Hale Telescope. All
spectra were reduced using the pyraf-dbsp pipeline (Bellm & Sesar 2016) and
spectral matching done using SNID and Superfit.

Name, Redshift, Classification, Notes
ATLAS17byq, z=0.045, SN Ia, best match is SN 1994D at -3 days
ATLAS17byo, z=0.03, SN Ia, best match is SN 2000dn at peak
ATLAS17cgg, z=0.02, SN IIn, best match is SN 1998S at -12 days