{
  "circularId": 42267,
  "eventId": "GRB 251013C",
  "createdOn": 1760470983935,
  "submittedHow": "web",
  "subject": "GRB 251013C: MarSEC, optical afterglow photometry ",
  "bibcode": "2025GCN.42267....1P",
  "format": "text/plain",
  "submitter": "I. Peretto at MarSEC (Marana Space Explorer Center) <ricerca@marsec.org>",
  "body": "Ivo Peretto (MarSEC, Marana Space Explorer Center, Marana Di Crespadoro, VI, Italy)\n\nMember of:\nUAI/SSV - Unione Astrofili Italiani/Sezione Stelle Variabili, GRB section.\nAAVSO (American Association Variable Stars Observers).\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) and Stefano Lora, Giovanni Furlato and Giuseppe Peretto (MarSEC, Marana Space Explorer Center, Marana di Crespadoro, VI, Italy) \nreport:\nWe imaged the field of GRB 251013C detected by SVOM (Rakotondrainibe et al., GCN 42222), with the robotic telescope of (IAU station 565) with the telescope 14” RC Officine Stellari of MarSEC (Marana Space Explorer Center) with CCD Moravian G2-1600-MKII.\n\nThe observations with a series of 90 sec exposures, 2025-10-13T23:13:26.703'UT of midpoint of exposure, with a Ritchey-Chretien telescope D=360 mm f/8. The afterglow was clearly detected at the following position:\n\nRA(J2000) = 23h 03m 20,7s\nDec(J2000) = -00d 13' 37\"\n\nWe report our photometry analysis:\n\n      HJD             Rc Mag   Err\n-------------------------------------\n2460962.4676701734    16.813   0.08\n\nWeather conditions were good, sqm medium 20,85\n\nWe co-added 14 exposures of 90 sec. each.\n\nMagnitudes were estimated with the pan-STARRS cat and are derived using Lupton (2005) equations and are not corrected for galactic dust extinction.\n\nReference:\nhttps://www.marsec.org/\n\nThe message may be cited. \n"
}