{
  "circularId": 37400,
  "eventId": "GRB 240825A",
  "createdOn": 1725568842110,
  "submitter": "Simone Leonini at Montarrenti Observatory (Siena, Italy) <s.leonini@iol.it>",
  "submittedHow": "web",
  "format": "text/plain",
  "bibcode": "2024GCN.37400....1L",
  "subject": "GRB 240825A: Montarrenti Observatory optical follow-up observations",
  "body": "S. Leonini, M. Conti, P. Rosi, L.M. Tinjaca Ramirez (Montarrenti Observatory, Siena, Italy, part of UAI/SSV-GRB section), A. Lorini, G. Verna (University of Siena – DSFTA), G. Bonnoli (INAF – Brera Astronomical Observatory) report:\n\nAs a follow-up of our early observations of the GRB 240825A (Fermi/GBM team, GCN 37273; Gupta et al., GCN 37274; Di Lalla et al., GCN 37288; Evans et al., GCN 37290; Gropp et al., GCN 37294; Kuin et al., GCN 37296; Joshi et al., GCN 37298; Sharma et al., GCN 37301; Frederiks et al., GCN 37302; Chen-Wei et al., GCN 37315; Moss et al., GCN 37355) already reported in GCN 37291, we kept on imaging the afterglow until 2024-08-26 01:32:48 UT with the same set-up and data analysis procedure. Observations were performed under thin cloud cover in the second part of the night. \n\nHere is our complete set of measurements:\n\n Observation Mid-Time     T-T0 (hr)    Exposure      Filter      Mag.      Err.\n2024-08-25  21:12:38 UT    5.33\t   \t50x40s\t       Rc       19.81    +/-0.10\n2024-08-25  21:47:40 UT    5.92\t\t60x40s\t       Rc       19.97    +/-0.11    \n2024-08-25  22:33:13 UT    6.66\t        60x40s\t       Rc       20.26    +/-0.12\n2024-08-25  23:18:46 UT    7.43\t\t58x40s         Rc       20.49    +/-0.16\n2024-08-26  00:04:19 UT    8.18\t\t50x40s         Rc       20.78    +/-0.22\n2024-08-26  00:49:57 UT    8.95\t\t60x40s         Rc       20.71    +/-0.19\n\nAlong the span of our observations and within our uncertainties, the afterglow evolves in agreement with a power-law decay with a rate alpha=1.87+/-0.20"
}