{
  "bibcode": "2009GCN.10116....1R",
  "body": "V. Rumyantsev, V. Biryukov (CrAO), A. Pozanenko (IKI)  report on behalf of \nlarger GRB follow-up collaboration:\n\nWe observed the field of  the Swift GRB 091024 (Marshall  et al., GCN 10062) \nwith ZTE telescope of  Crimean branch of SAI MSU in  R-filter on Oct.24 \nbetween  (UT) 16:18:50 - 00:04:47 and Oct.25 19:07:19 - 19:48:19 under \nmoderate seeing of about 3\". In initial images we detect fading afterglow \n(Mundell et al., GCN 10063). In a combined image of the Oct. 24 the \nafterglow looks like extended due to the nearby NW object reported by \nMoskvitin et al. (GCN 10101).\n\nIn a preliminary data reduction we do not separate afterglow and nearby \nobject. The astrometry of the afterglow + nearby object is following\n\nOct.24\nRA(J2000):  22 36 59.61\nDc(J2000): +56 53 23.1\nwith uncertainty of  0.5 arcsec\n\nOct.25\nRA(J2000):  22 36 59.33\nDc(J2000): +56 53 24.5\nwith uncertainty of  0.5 arcsec\n\nThe coordinates of Oct. 24 consistent with afterglow coordinates (Mundell et \nal., GCN 10063, Henden et al. GCN 10073, Chornock et al. GCN 10075). The \nangular distance between astrometry results is 2.7\"  suggests a prevalence \nof the afterglow on Oct.24 and nearby object on Oct.25. Taking into account \nthe redshift of z = 1.091 (Cucchiara et al. GCN 10065, Cenko et al. GCN \n10093) one can estimate the distance between afterglow and object as 22 kpc \nand the nearby object could be the host galaxy of GRB 091024 as suggested \nearly (Moskvitin et al. GCN 10101).\n\nA preliminary photometry of the afterglow+nearby object is based on \nreference star  USNO B1.0 1468-0448529 (22 36 55.66 +56 53 04.2) assuming \nR=17.30:\n\nT0+     Filter, Exposure, mag.,     err.\n(d)                (s)\n\n0.3210  R       600  18.31 +/-0.07\n0.3283  R       600  18.56 +/-0.08\n0.3356  R       600  18.72 +/-0.08\n0.3429  R       600  18.56 +/-0.08\n0.3522  R       600  18.73 +/-0.08\n0.3595  R       600  18.80 +/-0.09\n0.3668  R       600  18.89 +/-0.11\n0.3741  R       600  18.70 +/-0.08\n0.3814  R       600  19.20 +/-0.16\n0.3887  R       600  19.16 +/-0.16\n0.3960  R       600  18.86 +/-0.15\n0.4076  R       780  19.44 +/-0.34\n0.5706  R       1260 19.11 +/-0.08\n0.5873  R       1320 19.15 +/-0.09\n1.4386   R      2340  20.7  +/- 0.2\n\nWe caution that afterglow photometry above is contaminated by the nearby \nobject which we suggest as a candidate of host galaxy. The combined image \ncan be found at http://grb.rssi.ru/GRB091024/GRB091024a_091024_R_ZTE.gif\nwhere vertical tick points out the afterglow and horizontal one points out \nthe nearby object.",
  "circularId": 10116,
  "createdOn": 1257112815000,
  "email": "apozanen@iki.rssi.ru",
  "subject": "GRB 091024: optical observations",
  "submitter": "Alexei Pozanenko at IKI, Moscow  <apozanen@iki.rssi.ru>",
  "eventId": "GRB 091024"
}