TITLE:   GCN CIRCULAR
NUMBER:  25483
SUBJECT: LIGO/Virgo S190814bv : Magellan IMACS Spectrum of AT2019npv classified as a Type Ib supernova 
DATE:    19/08/27 03:33:34 GMT
FROM:    Sebastian Gomez at Harvard U  <sgomez@cfa.harvard.edu>

S. Gomez, G. Hosseinzadeh, E. Berger, P. K. Blanchard, T. Eftekhari, J. Gill, L. Patton,
V. A. Villar, P. K. G. Williams (Harvard U), P. S. Cowperthwaite (Carnegie Obs), R. Chornock (Ohio U),
W. Fong, R. Margutti, K. D. Alexander (Northwestern U), and M. Nicholl (U Edinburgh) report:

We observed AT2019npv (Goldstein et al. GCN 25393) with the IMACS optical spectrograph on the 
Magellan 6.5m telescope (Dressler et al. 2011) on 2019 Aug 26 09:26:09UT. We corroborate 
the redshift measurement of z = 0.056 from Jonker et al. (GCN 25454) and De. et al. 
(GCN 25480, 25461) by measuring the location of prominent host emision lines. We see 
mainly emision lines of Ca II 7291, 7323, O I 6300, and He I 5876. Leading to the 
classification of this transient as a Type Ib supernova, and therefore unrelated
to the LIGO event S190814bv (GCN 25324, GCN 25333). We find a best match to a supernova
~50 days after peak using template matching with SNID (Blondin & Tonry, 2007, ApJ, 666, 1024).

We thank Dave Osip for taking these observations at Magellan.