TITLE:   GCN CIRCULAR
NUMBER:  18341
SUBJECT: LIGO/Virgo G184098: Keck II DEIMOS Spectra of iPTF Optical Candidates
DATE:    15/09/20 01:53:22 GMT
FROM:    Mansi M. Kasliwal at Caltech  <mansi@astro.caltech.edu>

M. M. Kasliwal (Caltech), S. B. Cenko (NASA GSFC), Y. Cao (Caltech) and G.
Duggan (Caltech)

report on behalf of a larger collaboration

We obtained spectra of the following iPTF candidates with the DEIMOS
spectrograph on the Keck II telescope on 2015 Sep 17 between approx. 11.3
and 13.3 UTC. Cross-correlating with supernova spectral libraries (SNID and
Superfit), we find the following candidates are unlikely to be related:
iPTF15cym: Supernova, Type II, z~0.055
iPTF15cyo: Supernova, Type Ia, z=0.0296
iPTF15cyq: Supernova, Type II, z=0.063
iPTF15cys: Supernova, Type Ia, z~0.05

In addition, we note that iPTF15cyk is unlikely to be related due to its
high redshift. iPTF15cyn, iPTF14cyp and iPTF5cyt spectra are dominated by
nuclear continuum. Further analysis and follow-up is underway. We thank S.
R. Kulkarni for the DEIMOS observing time.

[GCN OPS NOTE(19sep15): This Circular was originally published on 09:28 18-Sep-2015 UT.]