{
  "circularId": 37123,
  "bibcode": "2024GCN.37123....1S",
  "createdOn": 1723255131226,
  "submitter": "Sam Shilling at Lancaster University <shilling.sam@gmail.com>",
  "submittedHow": "web",
  "format": "text/plain",
  "eventId": "GRB 240809A",
  "subject": "GRB 240809A: Swift/UVOT Detection",
  "body": "S.P.R. Shilling (Lancaster U.) and P. A. Evans (U. Leicester)\nreport on behalf of the Swift/UVOT team:\n\nThe Swift/UVOT began settled observations of the field of GRB 240809A\n98 s after the BAT trigger (Evans et al., GCN Circ. 37110).\nA source consistent with the enhanced XRT position\n(Osborne et al., GCN Circ. 37115) is detected in the initial UVOT exposures.\n\nThe preliminary UVOT position is:\n    RA  (J2000) =  15:50:10.52 = 237.54385 (deg.)\n    Dec (J2000) = -02:19:03.0  =  -2.31751 (deg.)\nwith an estimated uncertainty of 0.42 arc sec. (radius, 90% confidence).\n\nPreliminary detections using the UVOT photometric system\n(Breeveld et al. 2011, AIP Conf. Proc. 1358, 373) for the early exposures are: \n\nFilter         T_start(s)   T_stop(s)      Exp(s)           Mag\n\nwhite               98          248          147         14.42 +/- 0.02\nv                  640          660           19         16.11 +/- 0.14\nb                  565          585           19         16.28 +/- 0.09\nu                  310          560          246         15.13 +/- 0.03\nw1                 689          709           19         16.19 +/- 0.17\nm2                 665         1263           78         17.31 +/- 0.18\nw2                 616         1387           97         18.33 +/- 0.24\n\n\nThe magnitudes in the table are not corrected for the Galactic extinction\ndue to the reddening of E(B-V) = 0.249 in the direction of the burst\n(Schlegel et al. 1998)."
}