{
  "bibcode": "2025GCN.38771....1L",
  "submitter": "Simone Leonini at Montarrenti Observatory (Siena, Italy) <s.leonini@iol.it>",
  "subject": "GRB 250101A: Montarrenti Observatory optical observations and rebrightening",
  "createdOn": 1735781357818,
  "eventId": "GRB 250101A",
  "body": "S. Leonini, M. Conti, P. Rosi, L.M. Tinjaca Ramirez (Montarrenti Observatory, Siena, Italy, part of UAI/SSV-GRB section), M.G. Dainotti (National Astronomical Observatory of Japan), Y. Niino (Tokyo University, Institute of Astronomy) and K. Kalinowski (Aarhus University, Department of Physics and Astronomy) report:\n\nWe observed the field of GRB 250101A (Swift trigger 1278305, Page et al., GCN 38752) with the automated and remoted 0.53m Ritchey-Chretien telescope at Montarrenti Observatory (Siena, Italy, IAU code C88).\n  \nThe observations were started at 2025-01-01 18:03:48 UT (approximately 4.66 hours after burst) stacking a set of Rc-band CCD images. Observations were performed under thin cloud cover in the second part of the night. \n\nThe OT was detected at the following position:\n\nRA    (J2000.0)  02h 28m 16.56s  +/-0.05 \nDecl. (J2000.0) +19° 11' 39.82\"  +/-0.14\n\nPreliminary photometry was obtained using nearby PanSTARRS stars as follows: \n\nObservation Mid-Time  \tT-T0 (hr)       Exposure        Filter      Mag.       Err.\n2025-01-01  18:18:09 UT   4.92\t   \t 40x40s\t\t  Rc       20.09     +/-0.09\n2025-01-01  18:47:18 UT   5.40           43x40s   \t  Rc       20.09     +/-0.10\n\nAn optical rebrightening was observed as follows:\n\nObservation Mid-Time  \tT-T0 (hr)       Exposure        Filter      Mag.       Err.\n2025-01-01  19:45:22 UT   6.37\t    \t 36x40s\t  \t  Rc       19.63     +/-0.08\n\nMagnitude was calibrated with the nearby PanSTARRS stars converted using Lupton (2005) equations. No correction for galactic dust extinction was applied.\n\nOur observations are consistent with other already reported (Li et al., GCN 38753; Mohan et al., GCN 38754; Zhu et al., GCN 38755; Budnev et al., GCN 38756; Wu et al., GCN 38758; Moskvitin et al., GCN 38762; Odeh et al., GCN 38763, Hu et al., GCN 38764; D'Avino et al., GCN 38768; Escudero-Coca et al., GCN 38769), included those of the optical brightening (Moskvitin et al., GCN 38765).\n",
  "submittedHow": "web",
  "circularId": 38771,
  "format": "text/plain"
}