{
  "bibcode": "2010GCN.11420....1H",
  "body": "S. T. Holland (CRESST/GSFC/USRA) and\nC. W. Wolf (PSU)\nreport on the behalf of the Swift UVOT team:\n\n      The Swift/UVOT observed the field of GRB 101117B starting 63 s\nafter the BAT trigger (Wolf, et al., 2010, GCN Circ. 11411).  Settled\nobservations started at 82 s.  We detect the optical afterglow\n(Holland, 2010, GCN Circ. 11412) in the U, B, and white filters.  The\nrefined UVOT position is\n\n\n     RA (J2000)  11:32:00.54  =  173.00225 (deg)\n    Dec (J2000) -72:39:45.9   =  -72.66275 (deg)\n\nwith an estimated uncertainty of 0.43 arcsec (radius, 90% confidence,\nstatistical + systematic).  This is 1.16 arcsec northwest of the\nUVOT-enhanced XRT position (Goad, et al., 2010, GCN Circ. 11413).\n\n     Preliminary magnitudes, and 3-sigma upper limits for detecting a\nsource in the finding charts and in the co-added images, are\n\nFilter      T_start   T_stop    Exp(s)      Mag   Err\n-----------------------------------------------------------\nwhite (fc)       82      232       147     17.81 0.08 \n    u (fc)      295      545       246     18.68 0.15\n\n    v           626      646        20    >17.9\n    b           551      571        20     18.22 0.27\n    u           700     1325        59    >19.1\n uvw1           675     1300        78    >19.3\n uvm2           825     1275        58    >18.7   \n uvw2           601     1051        58    >19.0\nwhite           575      595        20     19.20 0.34\n-----------------------------------------------------------\n\n     The quoted magnitudes and upper limits have not been corrected\nfor the expected Galactic extinction along the line of sight\ncorresponding to a reddening of E_{B-V} = 0.38 mag (Schlegel, et al.,\n1998, ApJS, 500, 525).  All photometry is on the UVOT photometry\nsystem described in Poole et al. (2008, MNRAS, 383, 627).\n\n     The non-detection in the UVOT uvw1 filter, and the observed UVOT\nspectral energy distribution at 600 s, is consistent with GRB 101117B\nhaving a redshift of approximately z <= 3, although we can not rule\nout the non-detection in the ultraviolet being due to extinction in\nthe host galaxy.  The white light curve exhibits a power-law decay\nwith an index of alpha = -0.8 +/- 0.1 between 82 and 6005 s after the\nBAT trigger.",
  "circularId": 11420,
  "createdOn": 1290439534000,
  "email": "Stephen.T.Holland@nasa.gov",
  "subject": "GRB 101117B: Swift/UVOT Observations of the Optical Afterglow",
  "submitter": "Stephen Holland at USRA/NASA/GSFC/SSC  <Stephen.T.Holland@nasa.gov>",
  "eventId": "GRB 101117B"
}