{
  "bibcode": "2011GCN.11551....1I",
  "body": "S. Immler (CRESST/UMCP/GSFC) and G. Stratta (ASDC) report on behalf\nof the Swift/UVOT team:\n\nSwift UVOT started observing the field of GRB 110107A on January 8,\n2011 at 15:12 UT, approximately T+17.9 hours (Cummings, GCN Circ 11545).\n\nNo optical afterglow consistent with the XRT position (Stratta et al.,\nGCN Circ. 11547) is detected in individual or merged UVOT exposures.\nPreliminary 3-sigma upper limits using the UVOT photometric system\n(Poole et al. 2008, MNRAS, 383, 627) are:\n\nFilter      T_start   T_stop    Exp(s)      Mag\n-----------------------------------------------\nv            64,646   75,090      2247 >20.5\nu            64,609   74,538      1638 >21.2\n-----------------------------------------------\n\nThe quoted upper limits have not been corrected for the expected\nGalactic extinction along the line of sight corresponding to a\nreddening of E_{B-V} = 0.459 mag (Schlegel et al., 1998, ApJS, 500, 525).",
  "circularId": 11551,
  "createdOn": 1294687246000,
  "email": "stefan.m.immler@nasa.gov",
  "subject": "GRB 110107A: Swift/UVOT upper limits",
  "submitter": "Stefan Immler at NASA/GSFC  <stefan.m.immler@nasa.gov>",
  "eventId": "GRB 110107A"
}