TITLE: GCN CIRCULAR NUMBER: 27063 SUBJECT: LIGO/Virgo S200213t: AT2020ciz/ZTF20aamvnat, AT2020cjb/ZTF20aamvnth and 2020cjf/ZTF20aamvodd 10.4m GTC spectroscopy DATE: 20/02/14 05:52:57 GMT FROM: Alberto J. Castro-Tirado at IAA-CSIC A. J. Castro-Tirado, Y.-D. Hu (IAA-CSIC), A. F. Valeev and V. Sokolov (SAO-RAS), E. Fernandez-Garcia (IAA-CSIC), I. Carrasco and A. Castellon (UMA), M. D. Caballero-Garcia (ASU-CAS), S. B. Pandey (ARIES) and G. Lombardi (GRANTECAN, IAC, ULL), on behalf of a larger collaboration, report: Following the detection of AT2020ciz/ZTF20aamvnat, 2020cjf/ZTF20aamvodd and AT2020cjb/ZTF20aamvnth (Kasliwal et al. GCNC 27051) within the error area of the GW event S200213t (LVC, GCNC 27042), 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 Feb 13, 20:08 UT. Details follow: For AT2020ciz/ZTF20aamvnat, a magnitude r'= 19.08 +/- 0.03 at 21:11 UT is derived. The GTC spectrum shows double-peaked emission lines**(H-alpha, H-beta, H-gamma, He I 5876, He II 4686) at z = 0, all consistent with a cataclysmic variable in our Galaxy. For AT2020cjb/ZTF20aamvnth, a magnitude r'= 20.33 +/- 0.03 at 20:13 UT is derived. The GTC spectrum is consistent with a SN IIp (about 6 days after the maximum) at z = 0.0612 +/- 0.0005. For 2020cjf/ZTF20aamvodd, a magnitude r'= 24.5 + /- 0.3 at 22:42 UT is derived, implying a decay in brightness of about 4.5 mag when comparing to the reported ZTF value 18 h earlier (GCNC 27051). The low S/N ratio GTC spectrum shows a H-alpha emission line at z=0 superimposed on a red continuum starting from ~6000 A. We conclude that this object is a red dwarf in our Galaxy. Therefore we consider that AT2020ciz/ZTF20aamvnat, AT2020cjb/ZTF20aamvnth and 2020cjf/ZTF20aamvodd are unrelated to the S200213t GW alert.