TITLE: GCN CIRCULAR NUMBER: 40059 SUBJECT: GRB 250327B: VIRT Optical Upper Limit DATE: 25/04/04 16:21:28 GMT FROM: Priya Gokuldass at ERAU gokuldap@my.erau.edu
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 250327B (Bouchet et al., GCN 39888) detected by SVOM/ECLAIRs with the 0.5m Virgin Island Robotic Telescope (VIRT) at the University of the Virgin Islands' Etelman Observatory on 2025-03-28 starting at 06:52:58.6 (T-mid ~ T0 + 10.5 hrs). We performed a series of exposures in an R filter with a total exposure of 2560s. The weather conditions were partly cloudy during the hours of observation with an average airmass of 1.6.
We do not detect any source at the position reported by SAO/RAS (Moskvitin et al., GCN 39889). This non-detection is consistent with reported detections (Moskvitin et al., GCN 39889; Pankov et al., GCN 39906; Xin et al., GCN 39890; O’Neill et al., GCN 39891;Malesani et al., GCN 39893; Lian et al, GCN 39894; Shrestha et al., GCN 39896; Kumar et al., GCN 39904; Pérez-Fournon et al., GCN 39912; Ducoin et al., GCN 39897; Ducoin et. al., GCN 39930; Perley et al., GCN 39902; Dennefeld et al., GCN 39905; Tarasenkov et al., GCN 39913; Broens et. al., GCN 40006 and Siegel et. al., GCN 40009) and upper limits (Mo et. al., GCN 39914 and della Vecchia et. al., GCN 39969). We report the following 3-sigma upper limit:
T_mid ||Exposure ||Filter ||Limit T+ 10.5 hrs || 2560 s || R || > 20.8
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.
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