[vsnet-grb-info 24602] LIGO/Virgo S200105ae: AT2020oo 10.4m GTC spectroscopy

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  26701
SUBJECT: LIGO/Virgo S200105ae: AT2020oo 10.4m GTC spectroscopy
DATE:    20/01/11 09:47:25 GMT
FROM:    Alberto J. Castro-Tirado at IAA-CSIC  <ajct at 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 (UMA) and 
M. D. Caballero Garcia (ASU-CAS) and J. Font (GRANTECAN, IAC, ULL), on 
behalf of a larger collaboration, report:

Following the detection of AT2020oo/Gaia20add (Kostrzewa-Rutkowska et 
al. GCNC 26686) within the error area of the GW event S200105ae (LVC, 
GCNC 26640), we obtained an optical spectrum covering the range 
3700-7400 A with the 10.4m GTC telescope equipped with OSIRIS in La 
Palma (Spain) on Jan 10, 06:53 UT.

For AT2020oo/Gaia20add, a magnitude r'= 17.56 +/- 0.02 at 06:49 UT is 
derived. The GTC spectrum is consistent with a SN Ia at redshift z = 
0.0486 +/- 0.0005 (based on the emission lines of the host galaxy).

Therefore we consider that AT2020oo/Gaia20add is unrelated to the 
S200105ae GW alert.