Skip to main content
Testing. You are viewing the public testing version of GCN. For the production version, go to
New Announcement Feature, Code of Conduct, Circular Revisions. See news and announcements

GCN Circular 27063

LIGO/Virgo S200213t: AT2020ciz/ZTF20aamvnat, AT2020cjb/ZTF20aamvnth and 2020cjf/ZTF20aamvodd 10.4m GTC spectroscopy
2020-02-14T05:52:57Z (4 years ago)
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.
Looking for U.S. government information and services? Visit