TITLE: GCN CIRCULAR NUMBER: 39410 SUBJECT: GRB 250221A: AKO Optical Upper Limit DATE: 25/02/21 16:45:15 GMT FROM: Mohammad Odeh at Al Khatim Observatory M44 mshodeh@gmail.com
Mohammad Odeh (Al-Khatim Observatory, AKO, operated by the International Astronomical Center in Abu Dhabi, UAE), and Shaikha Alshamsi, Nuha Manal Pattani, and Nidhal Guessoum (American University of Sharjah, UAE), report: We observed the field of GRB 240221A (Swift BAT and XRT team, Caputo et al. GCN 39396, Beardmore et al., GCN 39404; Shilling et al., GCN 39409; COLIBRÍ/DDRAGO, Watson et al. GCN 39397; REM, Melandri et al. GCN 39406) with our 0.36m f/7.7 robotic telescope. The observation was performed on 21 February 2025 at 15:53: 37 UTC (mid-time), 12.32 hours after the trigger. We obtained 11x180s images using Ic filter at the position given by Swift/XRT: RA (J2000): 03h 57m 51.09s Dec (J2000): -15d 08' 00.6" We did not detect an afterglow candidate at the above position down to a magnitude of Ic = 19.7 for the stacked images. The magnitude was estimated using the Atlas catalogue as a reference. The magnitude is not corrected for galactic extinction.
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