GCN Circular 18791
Subject
LIGO/Virgo G211117: Liverpool Telescope classification of EM candidates
Date
2015-12-31T20:40:06Z (9 years ago)
From
Chris Copperwheat at LJMU ArI <c.m.copperwheat@ljmu.ac.uk>
In GCN 18782 we reported spectroscopic follow-up observations of a
number of the EM candidates reported by Cenko et al. in GCN 18762. We
now provide the following classifications using these data. All
observations were obtained using the 2.0 metre Liverpool Telescope, La
Palma by C.M. Copperwheat & I.A. Steele (Liverpool JMU) on behalf of a
wider collaboration.
iPTF-15ffi was observed with the SPRAT spectrograph on 2015-12-30 at
19:43UT. Classification using SNID (Blondin & Tonry, 2007, ApJ, 666,
1024) indicates the transient is a type Ia supernova with z = 0.073
-/+ 0.004 at 9.5 days past peak. This redshift is consistent with the
SDSS photometric redshift of the proposed host galaxy (z=0.079).
iPTF-15fel was observed with the SPRAT spectrograph on 2015-12-30 at
20:20UT. Classification using SNID indicates the transient is a type
Ia supernova with z = 0.042 -/+ 0.005 at 35.6 days past peak. This
redshift is consistent with the SDSS photometric redshift of the
proposed host galaxy (z=0.049).
iPTF-15fhq was observed with the SPRAT spectrograph on 2015-12-30 at
21:22UT. The spectrum shows a number of emission lines, and we believe
this source is most likely an AGN.
iPTF-15fev was observed with the SPRAT spectrograph on 2015-12-30 at
21:55UT. Classification using SNID indicates the transient is a type
Ia supernova with z = 0.020 -/+ 0.002 at 53.1 days past peak. This
redshift is consistent with the SDSS photometric redshift of the
proposed host galaxy (z=0.018).
iPTF-15fhl was observed with the SPRAT spectrograph on 2015-12-31 at
02:48UT. We detect a narrow emission line on top of the host galaxy
spectrum, which is at a wavelength consistent with H-alpha at the
proposed host galaxy redshift (z=0.044).
iPTF-15ffh was observed with the SPRAT spectrograph on 2015-12-30 at
19:04UT. These data were obtained in twilight and are of poorer
quality, and the spectrum we obtain appears to be dominated by the
host galaxy.