{
  "bibcode": "2009GCN..8846....1M",
  "body": "F.E. Marshall (NASA/GSFC) and D. Grupe (PSU)\nreport on behalf of the Swift/UVOT team:\n\nThe Swift/UVOT observed the field of GRB 090123 starting 107 s after\nthe BAT trigger (Grupe et al., GCN Circ. 8842). We detect the optical\nafterglow (Grupe et al.) in the white, v, b, u, uvw1, uvm2, and\nuvw2 filters at the position:\n\n  RA(J2000)  =  00:27:08.73 =   6.78639\n  DEC(J2000) = -23:30:04.1  = -23.50113\n\nwith an estimated uncertainty of 0.5 arc sec. (radius, 90% confidence).\nThere is a broad peak in the light curve ~600 sec. after the trigger.\nThe 3.4-sigma detection in the uvw2 filter indicates that the redshift \nis less than ~1.4.\n\nThe magnitudes in the UVOT photometric system \n(Poole et al. 2008, MNRAS, 383, 627) in the first finding chart (FC) \nexposure and subsequent exposures are:\n\nFilter          T_start(s)   T_stop(s)      Exp(s)       Mag \n\nwhite (FC)         107          257          147         17.8 +/- 0.1\nv                  649          669           20         15.4 +/- 0.1\nb                  575          595           20         15.8 +/- 0.1\nu                  320          570          250         16.4 +/- 0.1\nuvw1               698          718           20         17.3 +/- 0.23\nuvm2              1251         8112          294         19.6 +/- 0.25\nuvw2              1547         7843          413         20.5 +/- 0.29\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 \n(Schlegel et al. 1998).",
  "circularId": 8846,
  "createdOn": 1232731752000,
  "email": "marshall@milkyway.gsfc.nasa.gov",
  "subject": "GRB 090123: Swift/UVOT Observations",
  "submitter": "Frank Marshall at GSFC  <marshall@milkyway.gsfc.nasa.gov>",
  "eventId": "GRB 090123"
}