{
  "bibcode": "2009GCN.10041....1L",
  "body": "W.B. Landsman (NASA/GSFC) and M. Stamatikos (OSU/NASA/GSFC) report on  \nbehalf of the Swift/UVOT team:\n\nThe Swift/UVOT began settled observations of the field of GRB 091018  \n69s after the BAT trigger (Stamatikos et al., GCN 10034).    The  \nafterglow is well-detected in all seven UVOT filters at the position \nreported by Stamatikos et al.     The initial magnitudes are as follows:\n\nFilter    T_start(s) Exp(s)      Mag\nwhite         69    147     14.57 � 0.012\nwhite        860    147     16.48 � 0.018\n\nu            281    246     15.07 � 0.017\nu           6911    197     18.04 � 0.08\n\nv            610     19     16.4 � 0.14\nb            536     19     16.4 � 0.08\nuvw1         660     20     15.9 � 0.12\nuvm2         635     20     15.7 � 0.16\nuvw2         586     20     16.1 � 0.15\n\nThe detection in the uvw2 filter indicates a redshift less than z = 1.1, \nconsistent with the value of z= 0.971 reported by the Magellan group ( \nChen et al., GCN 10038).\n\nThe values quoted above are not corrected for the Galactic extinction  \ndue to the reddening of E(B-V) = 0.029 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": 10041,
  "createdOn": 1255925528000,
  "email": "wayne.b.landsman@nasa.gov",
  "subject": "GRB091018: Swift/UVOT observations",
  "submitter": "Wayne Landsman at GSFC/SSAI  <wayne.b.landsman@nasa.gov>",
  "eventId": "GRB 091018"
}