{
  "bibcode": "2020GCN.27063....1C",
  "body": "A. J. Castro-Tirado, Y.-D. Hu (IAA-CSIC), A. F. Valeev and V. Sokolov \n(SAO-RAS), E. Fernandez-Garcia (IAA-CSIC), I. Carrasco and A. Castellon \n(UMA), M. D. Caballero-Garcia (ASU-CAS), S. B. Pandey (ARIES) and G. \nLombardi (GRANTECAN, IAC, ULL), on behalf of a larger collaboration, report:\n\nFollowing the detection of AT2020ciz/ZTF20aamvnat, 2020cjf/ZTF20aamvodd \nand AT2020cjb/ZTF20aamvnth (Kasliwal et al. GCNC 27051) within the error \narea of the GW event S200213t (LVC, GCNC 27042), we obtained optical \nspectra covering the range 3700-7400 A with the 10.4m GTC telescope \nequipped with OSIRIS in La Palma (Spain) starting on Feb 13, 20:08 UT. \nDetails follow:\n\nFor AT2020ciz/ZTF20aamvnat, a magnitude r'= 19.08 +/- 0.03 at 21:11 UT \nis derived. The GTC spectrum shows double-peaked emission \nlines**(H-alpha, H-beta, H-gamma, He I 5876, He II 4686) at z = 0, all \nconsistent with a cataclysmic variable in our Galaxy.\n\nFor AT2020cjb/ZTF20aamvnth, a magnitude r'= 20.33 +/- 0.03 at 20:13 UT \nis derived. The GTC spectrum is consistent with a SN IIp (about 6 days \nafter the maximum) at z = 0.0612 +/- 0.0005.\n\nFor 2020cjf/ZTF20aamvodd, a magnitude r'= 24.5 + /- 0.3 at 22:42 UT is \nderived, implying a decay in brightness of about 4.5 mag when comparing \nto the reported ZTF value 18 h earlier (GCNC 27051). The low S/N ratio \nGTC spectrum shows a H-alpha emission line at z=0 superimposed on a red \ncontinuum starting from ~6000 A. We conclude that this object is a red \ndwarf in our Galaxy.\n\nTherefore we consider that AT2020ciz/ZTF20aamvnat, \nAT2020cjb/ZTF20aamvnth and 2020cjf/ZTF20aamvodd are unrelated to the \nS200213t GW alert.",
  "circularId": 27063,
  "createdOn": 1581659577000,
  "email": "ajct@iaa.es",
  "subject": "LIGO/Virgo S200213t: AT2020ciz/ZTF20aamvnat, AT2020cjb/ZTF20aamvnth and 2020cjf/ZTF20aamvodd 10.4m GTC spectroscopy",
  "submitter": "Alberto J. Castro-Tirado at IAA-CSIC  <ajct@iaa.es>",
  "eventId": "LIGO/Virgo S200213t"
}