{
  "bibcode": "2008GCN..8544....1O",
  "body": "S. R. Oates (MSSL-UCL) reports on behalf of the Swift/UVOT team:\n\nThe Swift/UVOT began settled observations of the field of GRB 081121,\n2816s after the BAT trigger (Oates et al., GCN Circ. 8537). We detect the\noptical afterglow in the white, v, b, u filters and marginally in the\nuvw1 filter at the position:\n\nRA(J2000.0)  =   5:57:06.15\nDEC(J2000.0) = -60:36:10.0\n\nwith an estimated uncertainty of 0.6 arcsec (radius, 90% confidence).\nThis position is consistent with the UVOT-enhanced XRT position\nand the position reported by ROTSE-IIIC (Yuan et al., GCN Circ. 8536).\n\nThe marginal detection of the optical afterglow in uvw1, and the lack\nof a detection in the uvm2 and uvw2 filters is consistent with a redshift\nof z=2.512 reported by Magellan (Berger and Rauch, GCN Circ. 8542).\n\nThe magnitudes and 3 sigma upper limits are reported below:\n\nFilter    T_start (s) T_stop  Exposure      Mag/3sig UL\n---------------------------------------------------------\nwhite       2816       2965     147       17.93 +/- 0.04\nv           2972       3172     197       17.58 +/- 0.08\nb           3792       3992     197       18.26 +/- 0.07\nu           3587       3787     197       17.62 +/- 0.06\nuvw1        3383       3582     197       20.60 +/- 0.48 (2.3-sigma)\nuvm2        3177       4813     393       > 20.09\nuvw2        4203       11200    790       > 20.78\n---------------------------------------------------------\n\nThe above magnitudes are not corrected for the Galactic extinction\ncorresponding to a reddening of E_{B-V} = 0.05 mag (Schlegel et al.,\n1998, ApJS, 500, 525).  The photometry is on the UVOT flight system\ndescribed in Poole et al. (2008, MNRAS, 383,627).",
  "circularId": 8544,
  "createdOn": 1227355982000,
  "email": "sro@mssl.ucl.ac.uk",
  "subject": "GRB081121: Refined Swift/UVOT observations",
  "submitter": "Samantha Oates at MSSL  <sro@mssl.ucl.ac.uk>",
  "eventId": "GRB 081121"
}