{
  "subject": "GRB 090813: Liverpool Telescope afterglow confirmation",
  "eventId": "GRB 090813",
  "bibcode": "2009GCN..9784....1S",
  "createdOn": 1250144230000,
  "circularId": 9784,
  "submitter": "James Smith at ARI,Liverpool John Moors U  <rjs@astro.livjm.ac.uk>",
  "email": "rjs@astro.livjm.ac.uk",
  "body": "R.J. Smith, I.A. Steele, Z. Cano (Liverpool JMU), C. Guidorzi (U.\nFerrara),  C.G. Mundell, A. Melandri, S. Kobayashi, C.J. Mottram,\nD.F. Bersier,  (Liverpool JMU), A. Gomboc (U. Ljubljana), report on behalf \nof a large collaboration:\n\nOn 2009 August 13 at 04:13:40.8 UT the 2-m Liverpool Telescope\nautomatically began observing the Swift GRB 090813 (Cummings et al.,\nGCN Circ. 9781) using the r' and i' filters. We confirm the detection by \nGorosabel et al (GCN 9782) and Cenko et al (GCN 9783) of an optical \ncounterpart to the XRT source. We measure a position of 15:03:05.9 \n88:34:05.5 J2000 with an uncertainty of 1arcsec and further, confirm the \nOT is fading. Ths position is 1 arcsec from and therefore conssitent from \nthat reported by Cenko et al (GCN 9783).\n\n\nMid Time     Delay from BAT   Total Exp  Filter     Mag\n(UT)\t     trigger (min)      (s)\n----------------------------------------------------------\n04:13:45.8      3.05\t\t10\tR\t19.36 +/- 0.13\n04:18:11.9      7.48\t\t120\tR\t19.90 +/- 0.05\n04:20:58.2     10.25\t\t120\tI\t18.11 +/- 0.02\n----------------------------------------------------------\n\nBoth astrometry and photometry is calibrated and quoted with respect\nto USNO-B.\n\nFurther observations are ongoing."
}