{
  "bibcode": "2010GCN.10730....1L",
  "body": "W.B. Landsman (GSFC) and R. Margutti (INAF-OAB)  report on behalf of the \nSwift/UVOT team.\n\nSwift/UVOT began settled observations of the field of GRB 100508A \nstarting 152 s after the BAT trigger (Margutti et al. GCN Circ. 10728).  \nAn uncatalogued fading source is seen in the 2.7' x 2.7' rapidly \navailable subimage within the XRT error circle at\n\n     RA(J2000) = 05h 04m 58.99s\n     Dec(J2000) = -20d 42' 41.1\"\n\nwith an uncertainty of about 0.6 arc sec (radius, 90% containment),   \nThe initial estimated magnitudes are as follows:\n\nFilter   T_start    Exp(s)      Mag  Err\n----------------------------------------------\nwhite       152       150     18.87  0.09\nu           310       250     19.25  0.20\nwhite       864       150     20.7   0.44\n----------------------------------------------\n\n\nThe above magnitudes are not corrected for the Galactic extinction \ncorresponding to a reddening of E_{B-V} = 0.87 (Schlegel et al.,\n1998, ApJS, 500, 525). The photometry is on the UVOT photometric system \ndescribed in Poole et al. (2008, MNRAS, 383, 627).",
  "circularId": 10730,
  "createdOn": 1273321229000,
  "email": "wayne.b.landsman@nasa.gov",
  "subject": "GRB100508A: Swift/UVOT Detection of the Afterglow",
  "submitter": "Wayne Landsman at GSFC/SSAI  <wayne.b.landsman@nasa.gov>",
  "eventId": "GRB 100508A"
}