{
  "bibcode": "2009GCN..9840....1G",
  "body": "D. Grupe (PSU), E. Hoversten (PSU) and Jay Cummings (NASA/GSFC)\nreport on behalf of the Swift  team:\n\nWe have analysed the XRT and UVOT data of the IPN burst GRB090823\n(Cummings et al. GCN Circ. 9835), beginning on 2009-08-24 at\n22:17, 30 hours after the Suzaku WAM trigger. The data contain 4.7\nks in XRT  photon counting mode. We clearly detect a possible X-ray\nafterglow within the 4' BAT error circle given by Cummings and Copete\net al. (GCN circs. 9838 and 9839, respectively) at\n  RA-2000,Dec-2000=128.67676, +60.65169 which corresponds to\n\nRA-2000 = 08h 34m 42.42s\nDec-2000 = +60d 39' 06.1\"\nwith an uncertainty of 5.5\"\n\nDuring the 4.7 ks observation on 2009-08-24 the X-ray source had a\ncount rate of (5.7+/-1.1)e-3 counts s-1 in the XRT which converts\nto an observed flux in the 0.3-10 keV band of (2.9+/-0.5)e-13\nergs s-1 cm-2 assuming a typical GRB afterglow spectrum.\n\n\nThe Swift/UVOT began settled observations of the field of GRB 090823\n108380 s after the BAT trigger (Cummings, et al., GCN Circ. 9835).\nNo optical afterglow consistent with the XRT position\nis detected in the initial UVOT exposures.\nPreliminary 3-sigma upper limits using the UVOT photometric system\n(Poole et al. 2008, MNRAS, 383, 627) for the initial exposures are:\n\nFilter         T_start(s)   T_stop(s)      Exp(s)         Mag\n\nwhite        109194       115699         1464         >21.8\nv               110009       116640         1680         >20.1\nu               108380       114954         1597         >20.7\n\nThe values quoted above are not corrected for the Galactic extinction\ndue to the reddening of E(B-V) = 0.06 in the direction of the burst\n(Schlegel et al. 1998).\n\nSwift is planning to re-observe the field of GRB 090823 on\n2009-08-27 for 10 ks in order to see if the X-ray source has faded.\n\n\nThis circular is an official product of the Swift team.",
  "circularId": 9840,
  "createdOn": 1251228000000,
  "email": "grupe@astro.psu.edu",
  "subject": "GRB 090823: Swift XRT possible detection of the X-ray afterglow",
  "submitter": "Dirk Grupe at PSU/Swift-XRT  <grupe@astro.psu.edu>",
  "eventId": "GRB 090823"
}