{
  "body": "L. Moretti, E. Pavoni (Leavitt Observatory, Italy)\n\nMembers of:\nGRB/UAI - Gamma Ray Burst Section of Unione Astrofili Italiani\nATA - Associazione Tuscolana di Astronomia\n\nIn a large collaboration with:\nM.G. Dainotti (National Astronomical Observatory of Japan), Y. Niino (Tokyo University, Institute of Astronomy), K. Kalinowski (Aarhus University, Department of Physics and Astronomy), report:\n\nWe observed the field of GRB 250702F detected by Fermi-GBM (GCN 40892) and Swift/UVOT (Klingler et al., GCN 40894), using our Ritchey-Chrétien telescope (D=250 mm, F/D=8).\n\nThe observations began approximately 0.5 hours after the trigger, ending at 2025-07-02T23:59:57 UT, stacking a set of CCD images of 180 seconds each, with good weather conditions. All images were processed by a single data processing pipeline based on astropy package (Astropy Collaboration et al., 2022ApJ...935..167A).\n\nThe optical afterglow reported by Jelinek et al. (GCN 40895), Kumar et al. (GCN 40896), Lipunov et al. (GCN 40899), Martin-Carrillo et al. (GCN 40900), de Ugarte Postigo et al. (GCN 40901), Angulo et al. (GCN 40907), Becerra et al. (GCN 40911), Brivio et al. (GCN 40913), An et al. (GCN 40916), Dutton et al. (GCN 40921) was clearly detected at the following coordinates:\n\nRA (J2000) =  14:11:44.65\nDec(J2000) = +16:44:54.59\n\n\nwith the following photometry: \n\nDate UT at mid-exposure         Exposure        Filter      Mag.   Mag. err.\n2025-07-02   21:38:43 UT        4x180s           CR       17.33    +/-0.21\n2025-07-02   21:52:08 UT        4x180s           CR       17.72    +/-0.21\n2025-07-02   22:05:47 UT        5x180s           CR       17.96    +/-0.21\n\n2025-07-02   22:19:44 UT        4x180s           R        18.13    +/-0.25\n2025-07-02   22:31:52 UT        4x180s           R        17.80    +/-0.21\n2025-07-02   22:44:01 UT        4x180s           R        18.02    +/-0.25\n2025-07-02   22:59:11 UT        5x180s           R        18.30    +/-0.21\n2025-07-02   23:17:29 UT        4x180s           R        18.80    +/-0.25\n2025-07-02   23:29:38 UT        4x180s           R        19.00    +/-0.25\n2025-07-02   23:47:50 UT        8x180s           R        19.30    +/-0.21\n\n\nCR magnitude is unfiltered with R zero point.\nR is Rc filter in Johnson-Cousins system.\n\nMagnitude was calibrated with the Pan-STARRS cat. and are derived using Lupton (2005) equations. Not corrected for galactic dust extinction.\n\nThis message may be cited.\n\n\nReference:\nhttps://leavittobservatory.altervista.org",
  "circularId": 40926,
  "createdOn": 1751568140430,
  "eventId": "GRB 250702F",
  "subject": "GRB 250702F: Leavitt Observatory optical observations",
  "submittedHow": "web",
  "submitter": "leavittob@gmail.com",
  "format": "text/plain",
  "bibcode": "2025GCN.40926....1M"
}