TITLE:   GCN CIRCULAR
NUMBER:  26405
SUBJECT: LIGO/Virgo S191205ah:  AT2019wfa 10.4m GTC spectroscopy
DATE:    19/12/13 07:19:30 GMT
FROM:    Alberto J. Castro-Tirado at IAA-CSIC  <ajct@iaa.es>

Y.-D. Hu (IAA-CSIC), A. F. Valeev (SAO-RAS), A. J. Castro-Tirado and E. 
Fernandez-Garcia (IAA-CSIC), V. Sokolov (SAO-RAS), I. Carrasco and A. 
Castellon (UMA) and R. Scarpa (GRANTECAN, IAC, ULL), on behalf of a 
larger collaboration, report:

Following the detection of Gaia19fmm (AT2019wfa, Kostrzewa-Rutkowska et 
al. GCNC 26397) within the error area of the GW event S191205ah (LVC, 
GCNC 26350), we obtained optical spectra covering the range 3700-7400 A 
with the 10.4m GTC telescope equipped with OSIRIS in La Palma (Spain) 
starting on Dec 12, 21:00 UT.

For Gaia19fmm/AT2019wfa a magnitude r' = 18.01 +/- 0.02 on MJD 
58829.8727669 is derived. The GTC spectrum is consistent with a SN Ia 
3-4 days before maximum at redshift z = 0.0599 +/- 0.0005 derived from 
the emission lines of the host galaxy.

Therefore we consider that Gaia19fmm/AT2019wfa is unrelated to the 
S191205ah GW alert.