{
  "bibcode": "2020GCN.28507....1O",
  "body": "S. R. Oates (U.Birmingham) and S. B. Cenko (GSFC)\nreport on behalf of the Swift/UVOT team:\n\nThe Swift/UVOT began settled observations of the field of GRB 200925B\n82 s after the BAT trigger (Cenko et al., GCN Circ. 28499).\nA source consistent with the XRT position (Beardmore et al. GCN Circ. 28503)\nand the optical position reported by the OSN\n(de Ugarte Postigo et al., GCN Circ. 28501) and MASTER\n(Lipunov et al., GCN Circ. 28502) is detected in the initial UVOT exposures.\n\nPreliminary detections and 3-sigma upper limits using the UVOT photometric\nsystem (Breeveld et al. 2011, AIP Conf. Proc. 1358, 373) for the early\nexposures are: \n\nFilter         T_start(s)   T_stop(s)      Exp(s)           Mag\n\nwhite (FC)      82          232           147        19.80 +/- 0.20\nwhite           574         1714          264        20.77 +/- 0.37\nv               623         1763          136        >18.9\nb               549         1689          117        >19.6\nu (FC)          294         544           246        >19.7\nu               294         1663          343        >19.9\nw1              672         1813          136        >19.0\nm2              1249        1441           39        >17.7\nw2              599         1739          117        >18.9\n\nThe magnitudes in the table are not corrected for the Galactic extinction\ndue to the reddening of E(B-V) = 0.04 in the direction of the burst\n(Schlegel et al. 1998).",
  "circularId": 28507,
  "createdOn": 1601151265000,
  "email": "samantha.oates@alumni.ucl.ac.uk",
  "subject": "GRB 200925B: Swift/UVOT Detection",
  "submitter": "Samantha Oates at MSSL  <samantha.oates@alumni.ucl.ac.uk>",
  "eventId": "GRB 200925B"
}