GCN Circular 27154
Subject
LIGO/Virgo S200213t: AT2020clw/ZTF20aanaoyz, AT2020crd/ZTF20aanakge and AT2020cly/ZTF20aanakes 10.4m GTC spectroscopy
Date
2020-02-20T15:31:10Z (5 years ago)
From
Alberto J. Castro-Tirado at IAA-CSIC <ajct@iaa.es>
Y.-D. Hu, A. J. Castro-Tirado (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), G.
Lombardi and S. Geier (GRANTECAN, IAC, ULL), on behalf of a larger
collaboration, report:
Following the detection of AT2020clw/ZTF20aanaoyz,
AT2020crd/ZTF20aanakge and AT2020cly/ZTF20aanakes (Kasliwal et al. GCNC
27051, Coughlin et al. GCNC 27095) 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). Details follow:
For AT2020clw/ZTF20aanaoyz, a magnitude r'= 21.10 +/- 0.09 at 2020-02-15
20:11 UT is derived. The GTC spectrum is consistent with a SN Ia (near
maximum) at z = 0.276 +/- 0.005.
For AT2020crd/ZTF20aanakge, a magnitude r'= 19.85 +/- 0.03 at 2020-02-19
20:42 UT is derived. The GTC spectrum is consistent with a SN Ia (near
maximum) at z = 0.1272 +/- 0.0005.
For AT2020cly/ZTF20aanakes, no optical counterpart is detected in the
r'-band 60s exposure image (2020-02-19 20:36UT) within the reported
position down to 24.9 mag at three-sigma confidence level, which
confirmed the non-detection reported by Bellm et al (GCNC 27118).
Therefore we consider that AT2020clw/ZTF20aanaoyz and
AT2020crd/ZTF20aanakge are unrelated to the S200213t GW alert.
We thank the staff at GTC for their excellent support.