{
  "bibcode": "2005GCN..3853....1B",
  "body": "I. Bikmaev, A. Galeev, N. Sakhibullin (KSU/AST),\nR. Burenin, M. Pavlinsky, R. Sunyaev (IKI),\nI. Khamitov, Z. Aslan (TUG), U. Kiziloglu (METU), E. Gogus (Sabanci Uni.),\n\nreport:\n\n      We have observed the OT of GRB 050820A (GCN 3829) with the\nRussian-Turkish 1.5-m telescope (Bakirlitepe, TUBITAK National\nObservatory, Turkey) in two consequative nights .\n      We made a series of exposures in Rc between UT 18:35 - 22:15, August \n20, 2005, and in BRcIc between UT 22:46-01:15, August 21/22, 2005. \nMoonlight produced variable background in all images for both nights. The \nafterglow is clearly detected in all bands. Using  Henden's stars (GCN 3845)\npresent in the frames,  we estimated the magnitudes as follow:\n\n   t-t0 \t\tBand \tmag      merr   exptime\n(hours, midtime)                       (sec,total)\n18.05 \t\tRc \t19.48 +/- 0.01   900\n41.42 \t\tRc \t20.38 +/- 0.05   1800\n40.93 \t\tB \t21.00 +/- 0.06   1800\n41.55 \t\tIc \t19.83 +/- 0.07   1800\n\n    On the basis of our Rc data, we estimeted an alpha index of power-law\ndecay for the observed period as ~ -1.0.\n\nThe JPG-images  of BRcIc and color combined image are available at:\n\nhttp://www.tug.tubitak.gov.tr/~irekk/grb/grb050820a/grb050820A_b.JPG\nhttp://www.tug.tubitak.gov.tr/~irekk/grb/grb050820a/grb050820A_r.JPG\nhttp://www.tug.tubitak.gov.tr/~irekk/grb/grb050820a/grb050820A_i.JPG\nhttp://www.tug.tubitak.gov.tr/~irekk/grb/grb050820a/grb050820_bri.JPG\n\nThis message may be cited.",
  "circularId": 3853,
  "createdOn": 1124714421000,
  "email": "irekk@tug.tug.tubitak.gov.tr",
  "subject": "GRB050820A: RTT150 optical observations",
  "submitter": "Irek Khamitov at TUG  <irekk@tug.tug.tubitak.gov.tr>",
  "eventId": "GRB 050820A"
}