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GCN Circular 18812

LIGO/Virgo G211117: Liverpool Telescope classification of EM candidates
2016-01-03T22:05:58Z (8 years ago)
Chris Copperwheat at LJMU ArI <>
We report the following spectroscopic observations and classifications
of two of the EM candidates reported by Cenko et al. in GCN 18762. 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-15ffh was observed with the SPRAT spectrograph on 2016-01-02 at
19:29UT. We previously observed this target in twilight and did not
detect the transient (GCN18791). The spectrum we obtained in this
second visit does not contain any obvious features, and a visual
inspection offers no clear classification. However, SNID (Blondin &
Tonry, 2007, ApJ, 666, 1024) provides a classification of a type Ia
supernova with z = 0.076 -/+ 0.007 at 22.2 days after peak. This
redshift is consistent with the spectroscopic redshift of the assumed
host galaxy (0.06857).

iPTF-15fhp was observed with the SPRAT spectrograph on 2016-01-02 at
23:31UT. In GCN18807 we reported a previous epoch of observation for
this transient in which we obtained a poor quality spectrum which SNID
classified as a type Ia supernova approximately one week before peak.
In this second visit the brightness of the target has not increased,
and so we would rule out this initial tentative classification. Again,
a classification is not obvious from a visual inspection of this
second epoch, but SNID reports this object is a type Ia supernova with
z=0.130 -/+ 0.007 at 4.1 days after peak.

Astrophysics Research Institute,
Liverpool John Moores University
Tel: +44 (0)151 231 2914
Fax: +44 (0)151 231 2921
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