{
  "bibcode": "2009GCN..9342....1K",
  "body": "N. P. M. Kuin (MSSL/UCL) and  E.A. Hoversten (PSU)  report on\nbehalf of the Swift UVOT team.\n\nThe Swift UltraViolet/Optical Telescope (UVOT) began observations of\nthe short hard burst GRB 090510 (Swift BAT trigger number 351588;\nHoversten et al. GCN Circ. 9331) on May 10, 2009, at 00:24:24 UT,\n80 seconds after the BAT trigger with a settling exposure in the\nUVOT v filter.\n\nA new optical source was found by the UVOT (Marshall and Hoversten,\nGCN Circ. 9332) for which we have a refined position (based on\nmatching the UVOT field sources to the USNO-B1 catalogue) of\nRA, DEC =  333.55208, -26.58311, which is equivalent to:\nRA = 22:14:12.5, DEC = -26:34:59.2, with an uncertainty of 1.5\"\n(90% confidence). The refined UVOT position is offset 1.6\" from\nthe refined XRT position (Goad et al., GCN Circ. 9339) and is\nconsistent with the revised NOT position (Malesani, GCN Circ. 9340)\nto within 0.2\".\t\n\nGRB 090510 is detected in all UVOT filters, except perhaps in b,\nwhich implies that the redshift is less than about 1.5. The\nemission is seen to rise to a peak around 600s after the trigger.\nThe initial magnitude observed in the UVOT filters are given below:\n\nFilter  Tstart(s)  Tstop(s)  Exposure(s)  Magnitude\n\nwh       97        247          147.4     19.63 +/- 0.17\nwh      588        608           19.5     18.76 +/- 0.22\nwh     1167       1526           58.3     19.16 +/- 0.20\nv        80       1410           97.3     18.46 +/- 0.33\nb       564       1502           97.2    >19.62 (2.2 sigma)\nu       712       1477          323.6     19.05 +/- 0.17\nuvw1    687       1452           75.9     18.61 +/- 0.27\nuvm2    662       1434           93.7s    18.10 +/- 0.22\nuvw2    614       1552          115.4s    18.31 +/- 0.18\n\nThe values quoted above are on the UVOT Photometric System\n(Poole et al, 2008, MNRAS 383,627). They are not corrected for the\nexpected galactic reddening of E(B-V) = 0.020 in the direction of\nthe burst (Schlegel et al. 1998).",
  "circularId": 9342,
  "createdOn": 1241974794000,
  "email": "npkuin@googlemail.com",
  "subject": "GRB 090510: UVOT refined analysis",
  "submitter": "Paul Kuin at MSSL  <npkuin@googlemail.com>",
  "eventId": "GRB 090510"
}