{
  "bibcode": "2024GCN.37313....1M",
  "subject": "GRB 240825A: SAO RAS optical observations",
  "body": "A. S. Moskvitin and O. I. Spiridonova (SAO RAS)\nreport on behalf of the GRB follow-up team.\n\nWe observed the field of the GRB 240825A (The Fermi GBM team,\nGCN 37273; Gupta et al., GCN 37274; Lalla et al., GCN 37288;\nEvans et al., 37290; Gropp et al., GCN 37294; Joshi et al.,\nGCN 37298; Sharma et al., GCN 37301; Frederiks et al., GCN 37302)\nwith the SAO RAS 1-meter telescope Zeiss-1000 equipped with the\nCCD-photometer on August 25/26, 26/27 and 27/28.\nThe weather conditions and seeing during the first and the second\nnights were poor. The third night was good.\nWe obtained series of exposures in Rc band on\n2024-08-25T20:37:53 -- 2024-08-25T22:32:59;\n2024-08-26T22:33:48 -- 2024-08-27T01:29:03;\n2024-08-27T19:51:04 -- 2024-08-27T21:15:46.\n\nThe OT (Gupta et al., GCN 37274; Jiang et al., GCN 37275;\nDutton et al., GCN 37276; Odeh and Guessoum, GCNs 37277, 37299;\nZhang et al., GCN 37278; Li et al., GCN 37280; Izzo and Malesani,\nGCN 37287; Lipunov et al., GCN 37289; Leonini et al., GCN 37291;\nWu et al., GCN 37292; Martin-Carrillo et al., GCN 37293;\nBrivio et al., GCN 37295; Kuin et al., GCN 37296; Le Floc’h et al.,\nGCN 37300; Zheng and Filippenko, GCN 37304; Wang et al., GCN 37306;\nMaksut et al., GCN 37307; Melandri et al., GCN 37310) is clearly\ndetected in the stacked frame only during the third night.\nThe non-detection of OT during our first and second nights is\nconsistent with the magnitudes reported by the other teams.\nOur results are following.\n\nDate       T_mid - T0, d  exp, s   magnitude\nAug 25     0.2378         1080     R_lim = 19.5\nAug 26/27  1.3392         1483     R_lim = 21.0\nAug 27     2.1948         4200     R = 21.88 +/- 0.07\n\nOur stacked frames are calibrated against nearby Pan-STARRS objects\nand not corrected for the MW extinction.\n",
  "circularId": 37313,
  "createdOn": 1724806275289,
  "submitter": "Moskvitin Alexander at SAO RAS <mosk@sao.ru>",
  "eventId": "GRB 240825A",
  "submittedHow": "email-legacy"
}