{
  "bibcode": "2023GCN.33192....1M",
  "body": "A. S. Moskvitin, O. I. Spiridonova and O. A. Maslennikova (SAO RAS),\nreport on behalf of the GRB follow-up team.\n\nWe observed the field of the GRB 230116D (Sonbas et al. GCN #33176)\nwith the SAO RAS 1-m telescope Zeiss-1000 + CCD-photometer in Rc band\non January 16/17 (21:55:22--00:36:40 UT) and 17/18 (21:42:43--23:31:38).\n\nDuring the first night the optical afterglow (Zhu et al., GCN #33177;\nNazarov et al., GCN #33178; Moskvitin et al. GCNs #33179, #33187;\nSwain et al., GCN #33182; Belkin et al., GCNs #33189, #33190, #33191)\nwas clearly detected in individual frames and shows complex behaviour.\n\nt-T0, h    R_mag  +/- err     exp, s\n0.844      19.967 +/- 0.070   300\n0.948      19.888 +/- 0.068   300\n1.045      19.874 +/- 0.066   300\n1.138      19.818 +/- 0.063   300\n1.233      19.674 +/- 0.057   300\n1.332      19.595 +/- 0.051   300\n1.432      19.701 +/- 0.055   300\n1.526      19.668 +/- 0.056   300\n1.623      19.779 +/- 0.062   300\n1.717      19.764 +/- 0.063   300\n1.820      19.728 +/- 0.058   300\n1.924      19.626 +/- 0.055   300\n2.022      19.539 +/- 0.052   300\n2.130      19.709 +/- 0.064   300\n2.226      19.798 +/- 0.070   300\n2.346      19.870 +/- 0.078   300\n2.444      19.976 +/- 0.083   300\n2.644      20.021 +/- 0.086   300\n2.835      20.065 +/- 0.066   2 x 300\n3.041      20.032 +/- 0.063   2 x 300\n3.241      20.138 +/- 0.062   2 x 300\n3.441      20.223 +/- 0.075   2 x 300\n\nWe also obtained 17 x 300 images in Rc band during the second night.\nThe OT is detected in the stacked frame with the brightness of\nR = 22.9 +/- 0.2 (t-T0 = 25.541h = 1.064d) which is in agreement with\nupper limit reported by Strausbaugh & Cucchiara (GCN #33188).\nPreliminary photometry is based on R2 magnitudes of nearby USNO-B1 stars.",
  "circularId": 33192,
  "createdOn": 1674014912000,
  "email": "mosk@sao.ru",
  "subject": "GRB 230116D: SAO RAS further observations",
  "submitter": "Moskvitin Alexander at SAO RAS  <mosk@sao.ru>",
  "eventId": "GRB 230116D"
}