{
  "createdOn": 1743423680919,
  "submittedHow": "web",
  "circularId": 39969,
  "bibcode": "2025GCN.39969....1V",
  "submitter": "Vincenzo Della Vecchia <v.dellavecchia@uai.it>",
  "body": "Vincenzo della Vecchia (45th Parallel Observatory, Italy)\n\nMember of:\nAAVSO - American Association of Variable Star Observers\nUAI - Unione Astrofili Italiani - Gamma Ray Burst Section\n\nIn a large collaboration with:\nM.G. Dainotti (National Astronomical Observatory of Japan),\nY. Niino (Tokyo University, Institute of Astronomy),\nK. Kalinowski (Aarhus University, Department of Physics and Astronomy),\nreport:\n\nWe imaged the field of GRB 250327B detected by SVOM (burst-id sb25032706, GCN Circular 39888) and Swift XRT (GCN circ. 39895) with the 0.25-m f/5.6 Ritchey-Chrétien telescope of the 45th Parallel Observatory (IAU code D43).\n\nThe observation started 22.33 hours after the GRB trigger, with acceptable sky transparency and seeing.\nA series of 10 sec observations has been added for a total integration time of approximately 30 minutes.\n\nStart T0+   End T0+     CR lim\n22.33 hour  22.83 hour  19.5\n\nCR as unfiltered with R zero point.\n\nNo optical counterpart has been detected at the position expected for the GRB.\n\nLimit magnitudes are estimated with the Pan-STARSS DR1 catalogue and are not corrected for galactic dust extinction.\nI am grateful to Ulisse Quadri (Bassano Bresciano Astronomical Observatory) for his support.\n\nThis message may be cited.",
  "format": "text/plain",
  "eventId": "GRB 202503",
  "subject": "GRB20250327B: 45th Parallel Observatory upper limit "
}