GCN Circular 27860
Subject
GRB 200528A: CAHA Upper Limit
Event
Date
2020-05-29T22:44:01Z (6 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), M. Blazek, C. C. Thoene, J. F. Agui Fernandez (all
HETH/IAA-CSIC), and I. Hermelo (CAHA) report:
We observed the XRT error circle (Evans et al., GCN #27836) of the
bright GRB 200528A (Swift detection: Ambrosi et al., GCN #27832; Fermi
GBM detection: The Fermi GBM team, GCN #27831) with the 2.2m telescope
at CAHA (Almeria, Spain), equipped with the CAFOS detector. We obtained
21 x 180 s exposures in the Ic band under adverse observing conditions
(moonlight, bad seeing and transparency).
At the enhanced XRT position, we detect no source (but would have
preferred to). We derive a 3 sigma limiting magnitude of Ic > 23.5 mag
(Vega) at 0.440865 days after the GRB, calibrated against SDSS standard
stars transformed to the Ic band following Lupton (2005). This limit is
comparable to those achieved by NOT about an hour later (Malesani et
al., GCN #27842).