{
  "bibcode": "2010GCN.11395....1V",
  "body": "A. Volnova (SAI MSU),  A. Pozanenko (IKI), M. Andreev, A. Sergeev\n(Terskol Branch\nof Institute of Astronomy),   V. Rumyantsev, K. Grankin (CrAO), A.\nErofeeva, G. Kornienko (UAFO), I. Molotov (ISON), E. Klunko (ISTPM),\nIbrahimov (MAO), B. Satovski (Astrotel) on behalf of GRB follow up\ncollaboration report:\n\nWe observed the optical afterglow (Markwardt et al. GCN 11227, Ivanov\net al. GCN 1128) of GRB 100906A (Markwardt et al. GCN 11227) with the\nfollowing telescopes: GAS-250 (Ussuriysk Astrophysical Observatory),\nAZT-14 (Mondy observatory), Zeiss-2000 and Zeiss-600 (Mt.Terskol\nobservatory),  Shajn telescope (CrAO) and AZT-22 (Maidanak\nobservatory). Observations started at 14:02 UT, i.e. approximately 13\nminutes after the burst trigger. Observations in different optical\nbands (B, V, R, I, g, r) cover the period of t-t_0 from 0.12 up to\n2.46 days. The photometry calibration was made against several stars\nof GSC2.3 catalog. The light curve of GRB 100906A afterglow can be\nfound at\nhttp://grb.rssi.ru/GRB100906A/GRB100906A_lc.png .\n\nFrom the R band of light curve one can see a clear break around ~0.5\ndays after the burst with alpha_1 = -0.7 +/- 0.1 before and alpha_2 =\n-2.0 +/- 0.3 after break.\nColor index B-R measured between 0.22 and 0.24 days after the burst\ndoes not change within the error bars and is equal to 1.33 +/- 0.12,\nwhile the B-R index measured at 1.26 days after the burst trigger is\nequal to 1.61+/- 0.19.",
  "circularId": 11395,
  "createdOn": 1289498207000,
  "email": "alinusss@gmail.com",
  "subject": "GRB 100906A: optical observations",
  "submitter": "Alina Volnova at SAI MSU  <alinusss@gmail.com>",
  "eventId": "GRB 100906A"
}