{
  "bibcode": "2009GCN..9758....1L",
  "body": "W.B. Landsman (NASA/GSFC) and C. Markwardt (CRESST/GSFC/UMD) report on \nbehalf of the Swift/UVOT team:\n\nThe Swift/UVOT began settled observations of the field of GRB 090809 \n108s after the BAT trigger (Markwardt et al., GCN Circ. 9754),      The \ntentative UVOT detection reported by Markwardt et al. is confirmed \nfollowing the downlink of additional data.   The UVOT position \ndetermined from the white finding chart exposure is\n\nRA (J2000)  21:54:43.19   =  328.679938 (deg)\nDec (J2000) -00:05:1.83   =  -0.083842 (deg)\n\nwith an estimated uncertainty of 0.6 arcsec (radius, 90% confidence,  \nstatistical + systematic), consistent with the NOT afterglow position \n(Xu et al., GCN Circ. 9755).\n\nThe initial magnitudes and upper limits are as follows:\n\nFilter   T_start(s) Tstop(s) Exp(s)      Mag\nwhite        108    194      84     19.53 +/- 0.14\nwhite       3396   3545     147     21.03 +/- 0.33\n\nv           3552   5181     393     19.87 +/- 0.30\nb           4365   5976     367    >21.1  (3 sigma)\nu           4162   5796     391    >20.8  (3 sigma)\nuvw1        3962   5592     393    >20.7  (3 sigma)\nuvm2        3757   5386     393    >20.5  (3 sigma)\nuvw2        4776  10964    1082    >21.6  (3 sigma)\n\nThe values quoted above are not corrected for the Galactic extinction \ndue to the reddening of E(B-V) = 0.10 in the direction of the burst \n(Schlegel  et al. 1998). The photometry is on the UVOT photometric \nsystem described in Poole et al. (2008, MNRAS, 383, 627).",
  "circularId": 9758,
  "createdOn": 1249882674000,
  "email": "wayne.b.landsman@nasa.gov",
  "subject": "GRB090809: Swift/UVOT observations",
  "submitter": "Wayne Landsman at GSFC/SSAI  <wayne.b.landsman@nasa.gov>",
  "eventId": "GRB 090809"
}