{
  "bibcode": "2005GCN..3698....1P",
  "body": "T. Poole (MSSL), A. Moretti (OAB), S. T. Holland (GSFC), M. Chester\n(PSU), L. Angelini (GSFC-JHU), N. Gehrels (GSFC) on behalf of the Swift\nUVOT team\n\nThe Swift Ultra-Violet/Optical Telescope (UVOT) began observations of\nGRB050726 (Barthlemy et al. GCN 3682) on 26th July 2005 at 05:02:07 UT.\nWe confirm the detection of a source inside the BAT and XRT error circle\n(Barthlemy et al. GCN 3682, A. Moretti et al. GCN 3683) in the V band\nonly. The source is detected in the initial V band observation, then \ndrops below the 3 sigma detection threshold. It is not detected in\nthe U, B or the UV filters.\n\nThe aperture used for all observations was 6 arcsec. The limiting\nmagnitudes are given to a 3 sigma limit.\n\nV filter\n\nstart  exposure mid     magnitude\ntime   time     time\nafter           after\nburst           burst\n(s)    (s)      (s)\n123    100      173    17.35+/-0.09 - source detection\n298    10       303    17.47        - limiting magnitude\n382    10       387    17.43        - limiting magnitude\n466    10       471    17.36        - limiting magnitude\n551    10       556    17.29        - limiting magnitude\n635    10       640    17.49        - limiting magnitude\n720    10       725    17.40        - limiting magnitude\n9825   900      10275  19.76        - limiting magnitude\n21647  900      22097  19.83        - limiting magnitude\n\nOther filters - limiting magnitudes\n\nFilter    start  exposure mid     limiting\n           time   time     time    magnitude\n           after           after\n           burst           burst\n           (s)    (s)      (s)\nb         269    59       485     19.38\nb         4992   1800     6189    21.31\nb         29659  12       29665   18.72\nu         255    59       216     19.23\nu         4124   2700     16888   21.06\nuvw1      241    59       457     19.29\nuvw1      4020   100      4070    19.49\nuvw1      11639  2003     17763   21.44\nuvm2      352    68       196     19.41\nuvm2      10731  1800     19738   21.48\nuvw2      284    89       500     19.88\nuvw2      5939   1300     13820   21.62\n\nThe magnitudes are based on preliminary zero points, measured in orbit,\nand will require refinement with further calibration.\n\nThis message may be cited.",
  "circularId": 3698,
  "createdOn": 1122650808000,
  "email": "tsp@mssl.ucl.ac.uk",
  "subject": "GRB050726: Swift UVOT observations",
  "submitter": "Tracey Poole at MSSL  <tsp@mssl.ucl.ac.uk>",
  "eventId": "GRB 050726"
}