GCN Circular 40900
Subject
GRB 250702F: NOT observations of the optical afterglow
Event
Date
2025-07-02T23:14:56Z (a day ago)
From
Antonio Martin-Carrillo at UCD,Space Science Group <antonio.martin-carrillo@ucd.ie>
Via
Web form
A. Martin-Carrillo (UCD), D. B. Malesani (DAWN/NBI and Radboud), G. Corcoran (UCD), B. P. Gompertz (Birmingham), A. de Ugarte Postigo (LAM), A. K. Haris-Kiss (Helsinki Univ.), N. Routamo (Helsinki Univ.), A. A. Djupvik (NOT) report on behalf of a larger collaboration:
We observed the field of GRB 250702F detected by Swift (Klingler et al., GCN 40894) and Fermi (Fermi GBM team, GCN 40892), using the StanCam camera mounted on the Nordic Optical Telescope (NOT). We obtained 3x90 s exposures in each of the Bessel-R and SDSS g and i bands, starting at 22:24 UT on 2025-07-02 (77 min after the Swift trigger).
The optical afterglow reported by Swift/UVOT (Klingler et al., GCN 40894), Ondrejov D50 (Jelinek et al., GCN 40895), GOTO (Kumar et al., GCN 40896) and MASTER (Lipunov et al., GCN 40899) is well detected in all bands. We measure the following coordinates (J2000, calibrated against Gaia stars):
RA = 14:11:44.65
Dec = +16:44:54.7
The object had a magnitude
r = 17.99 +/- 0.08 (AB).
The photometric calibration was performed using nearby stars from the Pan-STARRS catalog and the magnitude is not corrected for Galactic extinction.