GCN Circular 30992
Subject
Possible Short GRB 211023B: CAHA 2.2m Detection
Date
2021-10-25T14:56:49Z (3 years ago)
From
Alexander Kann at IAA-CSIC <kann@iaa.es>
D. A. Kann (HETH/IAA-CSIC), A. de Ugarte Postigo (HETH/DARK/NBI), C. C.
Thoene, M. Blazek, J. F. Agui Fernandez (all HETH/IAA-CSIC), A.
Guijarro, and P. Martin-Fernandez (both CAHA) report:
We observed the optical afterglow of the potentially short Swift GRB
211023B (Dichiara et al., GCN #30960; Kuin & Dichiara, GCN #30975) with
CAFOS mounted on the 2.2m Telescope at Calar Alto, Almeria, Spain. We
obtained 30 x 90 s in the SDSS i' band under mediocre conditions.
At the position of the GRB afterglow discovered by Swift/UVOT (Kuin &
Dichiara, GCN #30975), we detect a source. Against two Pan-STARRS
comparison stars, we measure:
i' = 22.26 +\- 0.10 mag (AB) at 0.3091 d after the GRB.
We note this faint magnitude is in agreement with both earlier (Lipunov
et al., GCN #30964; Pozanenko et al., GCN #30972; Yu et al., GCN
#30976), simultaneous (Yu et al., GCN #30976), and later (Watson et al.,
GCN #30973) non-detections.