{
  "bibcode": "2009GCN..9067....1S",
  "body": "P.Schady (MSSL-UCL) and S.R.Oates report on behalf of the Swift/UVOT  \nteam\n\nFollowing from the tentative UVOT afterglow detection of GRB090401B  \nreported in Schady et al. (GCN 9066), we here report a fading by over  \ntwo magnitudes between the two UVOT white finding charts, taken 792s  \napart at the following position\n\nRA (J2000) = 06:20:21.11 (95.08775deg)\nDec (J2000) = -08:58:19.5 (-8.97199deg)\n\nwith an estimated uncertainty of 0.5 arcsec (radius, 90% confidence),  \nsuggesting this to be the optical afterglow of GRB090401B. This  \nposition falls on a known source, making absolute magnitudes and a  \nprecise localisation difficult at this stage, and further data will be  \nrequired in order to carry out source subtraction.\n\nThe values quoted above are not corrected for the Galactic extinction  \ndue to the reddening of E(B-V)  = 0.67 in the direction of the burst  \n(Schlegel et al. 1998). All photometry is on the UVOT photometry  \nsystem described in Poole et al. (2008, MNRAS, 383, 627).",
  "circularId": 9067,
  "createdOn": 1238578748000,
  "email": "ps@mssl.ucl.ac.uk",
  "subject": "Swift/UVOT detection of GRB090401B",
  "submitter": "Patricia Schady at MSSL/Swift  <ps@mssl.ucl.ac.uk>",
  "eventId": "GRB 090401B"
}