GCN Circular 40920
Subject
GRB 250424A: VIRT Optical Upper Limit
Event
Date
2025-07-03T15:22:30Z (a year ago)
From
Priya Gokuldass at ERAU <gokuldap@my.erau.edu>
Via
Web form
K. Smith (UVI), P. Gokuldass (ERAU), N. Orange (OrangeWave Innovative Science, LLC), B. Gendre (UVI), D. Morris (NASA), T. Lombardi (Eckerd College), F. George (ERAU), D. Smith (UVI), C. Watson (UVI) report:
We observed the field of GRB 250424A (Cenko et al., GCN 40224) detected by Swift/BAT with the 0.5m Virgin Island Robotic Telescope (VIRT) at the University of the Virgin Islands' Etelman Observatory on 2025-05-06 starting at 02:22:01.68 UTC (T-mid ~ T0 + 7d 3.45h). We performed a series of exposures in an R filter with a total exposure of 2860s. The weather conditions were partly cloudy during the hours of observation with an average airmass of 1.8.
We do not detect any source at the enhanced XRT position reported (Evans et al., GCN 40232). This non-detection is consistent with reported detections (Francile et al., GCN 40222; Brivio et al., GCN 40225; de Wet et al., GCN 40229; Becerra et al., GCN 40226; Saccardi et al., GCN 40228; Siegel et al., GCN 40244; Dutton et al., GCN 40241; Schneider et al., GCN 40250; Ducoin et al., GCN 40230; Turpin et al., GCN 40240; Elkabir et al., GCN 40251; Ghosh et al., GCN 40263; de Ugarte Postigo et al., GCN 40461 ) and upper limits (Lipunov et al., GCN 40223; Siegel et al., GCN 40244). We report the following 3-sigma upper limit:
T_mid ||Exposure ||Filter ||Limit
T+ 7d 3.45h || 2860 s || R ||> 20.7
The limit is estimated from comparison to nearby USNO B1 stars and is not corrected for Galactic extinction.
We acknowledge financial support from NASA EPSCoR award 80NNSC22M0063, NSF PAARE award 2319415, and NASA EPSCoR award 80NSSC24M0112. This message can be cited.