{
  "bibcode": "2009GCN..9774....1S",
  "body": "P. Schady (MSSL-UCL) and M. Stamatikos (NASA/ORAU) report on behalf of the \nSwift UVOT team:\n\nThe Swift/UVOT began settled observations of the field of GRB 090812 86s \nafter the BAT trigger (Stamatikos et al., GCN Circ. 9768). An \nuncatalogued, fading source is detected in the UVOT white, v, b and u band \nfilters at the position reported in Stamatikos et al. (GCN Circ. 9768), \nconsistent with the refined XRT error circle (Goad et al., GCN Circ. \n9772). The detection of the afterglow in the white, v, b and u filters is \nconsistent with the spectroscopic redshift of z=2.452 reported by Ugarte \nPostigo et al. (GCN Circ. 9771). Early time UVOT obserations indicate a \ndecay rate of alpha~1.5.\n\nThe magnitudes and 3-sigma upper limits for the UVOT observations of GRB \n090812 in each filter are as follows:\n\nFilter  T_start(s)  T_stop(s)  Exp(s)  Mag/3-sig UL\nwhite      86         235       146    17.35+/-0.03\nv          628        647       19     18.17+/-0.41\nb          554        573       19     18.62+/-0.28\nu          299        548       246    18.65+/-0.11\nuvw1       677        1124      58     > 19.20\nuvm2       652        1099      58     > 18.72\nuvw2       603        1050      58     > 19.13\n\nThe values quoted above are not corrected for the Galactic extinction due \nto the reddening of E(B-V) = 0.02 in the direction of the burst (Schlegel \net al. 1998). The photometry is on the UVOT photometric system described \nin Poole et al. (2008, MNRAS, 383, 627).",
  "circularId": 9774,
  "createdOn": 1250085151000,
  "email": "ps@mssl.ucl.ac.uk",
  "subject": "GRB090812: Swift/UVOT observations",
  "submitter": "Patricia Schady at MSSL/Swift  <ps@mssl.ucl.ac.uk>",
  "eventId": "GRB 090812"
}