GCN Circular 29725
Subject
GRB 210321A: OSN Upper Limit
Event
Date
2021-03-24T23:41:30Z (5 years ago)
From
Alexander Kann at IAA-CSIC <kann@iaa.es>
D. A. Kann (HETH/IAA-CSIC), A. de Ugarte Postigo (HETH/IAA-CSIC,
DARK/NBI), C. C. Thoene, M. Blazek, J. F. Agui Fernandez (all
HETH/IAA-CSIC), and F. Aceituno (IAA-CSIC) report:
We observed the optical afterglow (Perri et al. GCN #29678; Siegel et
al. GCN #29679; Butler et al. GCN #29680; Heintz et al. GCN #29684; Xin
et al., GCN #29687; Pankov et al., GCNs #29689, #29692; Laporte et al.,
GCN #29697) of GRB 210321A (Swift detection: Dichiara et al., GCN
#29677) with the 1.5m T150 telescope of the Observatorio de Sierra
Nevada (OSN), Granada, Spain. Observations could not be taken due to
high winds in the first night after the GRB. We obtained 11 x 180 s
exposures in Rc starting at 2021-03-22 19:59:44.93 UT, before high winds
shut the telescope down again. The afterglow is not detected in the
combined image.
We determine an upper limit Rc > 23.3 mag (AB mag, vs. a nearby
Pan-STARRS star converted to Rc following the Lupton transformations,
then transformed back to AB mag) at 1.5437 days after the GRB.