GCN Circular 33696
Subject
GRB 230427A : OHP/T193 optical upper limit
Date
2023-04-27T23:52:46Z (a year ago)
From
Damien Turpin at CEA-Saclay <dturpin-astro@hotmail.com>
D. Turpin (CEA Paris-Saclay), C. Adami (LAM), B. Schneider (MIT),
S. Basa (LAM), E. Le Floc'h, D. Turpin, D. Götz (CEA Paris-Saclay),
S. D. Vergani (GEPI, Obs. de Paris), report on behalf
of a larger collaboration:
We observed the field of GRB 230427A (Troja et al., GCN 33687)
using the T193cm telescope at Observatoire de Haute-Provence (France)
equipped with the MISTRAL spectro-imager. 18 exposures were obtained
in the r-band (16x300s + 2x60s) from 2023 27 April 20:36:47 UT to
2023 27 April 22:59:06 UT (mid time ~11.27h after trigger). In the combined
frame, we do not detect any source at the UVOT position reported by
Troja et al., GCN 33687 and the enhanced XRT position (Beardmore et al.,
GCN 33688) down to the following 3-sigma limit:
r > 22.3 mag (AB)
The photometric calibration was performed using nearby stars from
the PanSTARRS catalog and the magnitude is not corrected for Galactic
extinction.
We acknowledge the excellent support from Observatoire de Haute-Provence,
in particular Jean Balcaen.