{
  "submitter": "Alan Watson at UNAM <alan@astro.unam.mx>",
  "circularId": 39136,
  "submittedHow": "email",
  "bibcode": "2025GCN.39136....1W",
  "body": "Alan M. Watson (UNAM), Dalya Akl (AUS), Camila Angulo (UNAM), Sarah\nAntier (OCA), Rosa L. Becerra (Università degli Studi di Roma Tor\nVergata), Stéphane Basa (UAR Pytheas), William H. Lee (UNAM), Jean-Luc\nAtteia (IRAP), Nathaniel R. Butler (ASU), Damien Dornic (CPPM),\nFrancis Fortin (IRAP), Jean-Grégoire Ducoin (CPPM), Francesco Magnani\n(CPPM), Margarita Pereyra (UNAM), Benjamin Schneider (LAM)\n\nand the DDRAGO engineering team:\n\nLuis Carlos Álvarez (UNAM), Fernando Angeles, Salvador Cuevas (UNAM),\nFrançois Dolon (OHP), Alejandro Farah (UNAM), Johan Floriot (LAM),\nJorge Fuentes-Fernández (UNAM), Arthur Langios (IRAP), Rosalía\nLangarica (UNAM), Simona Lombarda (LAM), Jaime Ruíz Díaz-Soto (UNAM),\nSamuel Ronayette (CEA), Silvio Tinoco (UNAM), and Hervé Valentín\n(IRAP)\n\nreport:\n\nWe imaged the field of the Swift GRB 250129A (Beardmore et al., GCN\nCirc. 39066) with the COLIBRÍ (SVOM/F-GFT) telescope at the\nObservatorio Astronómico Nacional on the Sierra de San Pedro Mártir in\nMexico.\n\nWe observed with the DDRAGO wide-field science camera (Langarica et\nal., 2024, Proc SPIE 13096, 130963D) in a filter that closely\napproximates Pan-STARRS r, from 2025-02-03 07:45 to 08:00 UTC, at a\nmidpoint of 5.20 days after the event, and obtained 600 seconds of\nexposure at a median airmass of 2.25 and good weather conditions. The\ndata were reduced using custom software and then analysed and\ncalibrated against the PS1 catalog using STDPipe (Karpov 2021).\n\nWe clearly detect the afterglow with\n\nr = 22.10 +/- 0.15\n\nThis magnitude is not corrected for Galactic extinction. Our\nmeasurement is consistent with the magnitude reported by Bochenek &\nPerley (GCN Circ. 39131) at 4.93 days after the event.\n\nFurther observations are planned.\n\nThe DDRAGO camera is still being commissioned, and these are its first\nscience observations. We warmly thank the COLIBRÍ engineering team and\nthe staff of the Observatorio Astronómico Nacional on the Sierra de\nSan Pedro Mártir.\n",
  "subject": "GRB 250129A: COLIBRÍ/DDRAGO Afterglow Detection",
  "createdOn": 1738613436998,
  "eventId": "GRB 250129A"
}