{
  "bibcode": "2007GCN..7116....1D",
  "body": "M. De Pasquale, P. Schady (MSSL-UCL) and J. Cummings (GSFC/GWU)\nreport on behalf of the Swift/UVOT team:\n\n  The Swift/UVOT began observing the field of GRB 071118 (Cummings\net al, GCN 7106) 123s after the BAT trigger.\n\n  In the v band finding chart, an uncatalogued source is detected\ninside the refined XRT error circle (Moretti et al 7111) with ~6\nsigma significance. This source looks extended; however it is not\nfound at late times, which indicates that it is the optical\nafterglow of GRB 071118. Its detection suggests that this GRB\ntook place at redshift z<~5. The coordinates of this source are\n\n  RA:    19 58 51.8\n  Dec:  +70 07 29.2\n\n  with an error of 0.6 arcsecond. No new source is detected within\nthe XRT error circle in the b, u or uv filters, either in the single\nor co-added exposures.\n\n  In the table below, we indicate the magnitude of the optical\nafterglow and the 3sigma upper limits. We do caution that the\nphotometry may be affected by the halo of a near bright star and\nthe crowded field.\n\n  Filter   Time (s)  Exp time (s)        Mag\n\n  White    134-233      98            > 20.6\n\n  White    734-743      9.8           > 19.4\n\n  White    874-973      98          20.4 +/- 0.2\n\n  White  1484-1983      39            > 20.6\n\n  White  5756-7391     393            > 21.4\n\n\n   v       240-639     393          19.1 +/- 0.2\n\n   v       774-793     9.8            > 18.1\n\n   v      981-1380     393          19.1 +/- 0.2\n\n   v     1524-2033      78            > 19.1\n\n   v     6166-7801     198            > 19.2\n\n   v   17862-18769     885            > 20.4\n\n\n   b      720-1696      87            >20.0\n\n   b     5551-7186     393            >20.6\n\n\n   u      695-2093     122            >20.0\n\n   u    5345-13654    1096            >21.0\n\n\n  w1      670-2083     136            >19.9\n\n  w1     6576-6775    1078            >21.2\n\n\n  um2     646-2058     136            >20.4\n\n  um2   11126-18883   1250            >21.2\n\n\n  uw2     750-2009      98            >19.7\n\n  uw2   6371-18883     750            >21.1\n\n\n  No correction has been made for the expected high\nGalactic extinction, corresponding to E(B-V) of 0.37.",
  "circularId": 7116,
  "createdOn": 1195488894000,
  "email": "mdp@mssl.ucl.ac.uk",
  "subject": "Swift/UVOT observations of GRB071118",
  "submitter": "Massimiliano de Pasquale at MSSL-UCL  <mdp@mssl.ucl.ac.uk>",
  "eventId": "GRB 071118"
}