TITLE:   GCN CIRCULAR
NUMBER:  26521
SUBJECT: LIGO/Virgo S191213g: AT2019wxt 10.4m GTC spectroscopy
DATE:    19/12/20 21:30:58 GMT
FROM:    Eleonora Troja at NASA/GSFC/UMD  <eleonora@umd.edu>

J. Becerra-Gonzalez (IAC), R. Sanchez-Ramirez (INAF-IAPS), E. Troja (UMD),
A. Watson (UNAM), O. Lopez-Cruz (INAOE), and W. H. Lee (UNAM)
on behalf of a larger collaboration, report:

Following the discovery of AT2019wxt/PS19hgw (McBrien et al., GCN 26485)
within the error area of the GW event  S191213g (LVC, GCN 26402), we
obtained optical spectra with the 10.4m GTC telescope equipped
with OSIRIS at La Palma (Spain). Observations were performed under good
weather conditions, low airmass, and a seeing ~1 arcsec.
They started on December 19 at 21:45 UT, and consisted in 3x300s
exposures using both R1000B and R2500I grisms,
covering the spectral range of ~3700-10000A.

Our spectra show a blue continuum with evident Balmer absorption features,
as well as several narrow emission lines at a common redshift of z=0.036,
in agreement with previous reports (Dutta et al., GCN 26490; Izzo et al.,
GCN 26491; Srivastav and Smartt, GCN 26493; Muller Bravo
et al., GCN 26494, Vogl et al., GCN 26504; Vallely et al., GCN 26508).
The luminosity, color evolution, and spectral features of this transient
do not match well with the properties of a kilonova, and instead are
consistent with a SNIIb (Vogl et al., GCN 26504; Vallely et al., GCN 26508).

Therefore we consider AT2019wxt to be unrelated to the GW event S191213g.