{
  "bibcode": "2018GCN.22805....1B",
  "body": "A. A. Breeveld (UCL-MSSL) and P. A. Evans (U. Leicester) report on \nbehalf of the Swift/UVOT team:\n\nThe Swift/UVOT began settled observations of the field of GRB 180620A \n270 s after the BAT trigger (Evans et al., GCN Circ. 22798).\nA fading source consistent with the XRT position (Osborne et al. GCN \nCirc. 22802), and also detected by Butler et al. (GCN Circ. 22799), \nElenin et al. (GCN Circ. 22800), Tyurina et al. (GCN Circ. 22801) and \nGuidorzi et al. (GCN Circ. 22803), is detected in the initial UVOT \nexposures. The detection in the UVOT uvw2 filter implies a redshift \nlimit of 1.2.\n\nThe preliminary UVOT position is:\n     RA  (J2000) =  18:39:35.09 = 279.89619 (deg.)\n     Dec (J2000) = +23:14:39.1  =  23.24419 (deg.)\nwith an estimated uncertainty of 0.43 arc sec. (radius, 90% confidence).\n\nPreliminary detections using the UVOT photometric system (Breeveld et \nal. 2011, AIP Conf. Proc. 1358, 373) for the early exposures are:\n\nFilter         T_start(s)   T_stop(s)      Exp(s)           Mag\n\nwhite              270          420          147         17.68 �� 0.04\nv                  427         1420          117         18.43 �� 0.19\nb                  525          717           39         18.77 �� 0.20\nu                  500          692           39         17.92 �� 0.17\nw1                 476         2158          194         18.86 �� 0.20\nm2                 623         7111          391         19.65 �� 0.27\nw2                 574         8136          588         20.00 �� 0.23\n\nThe magnitudes in the table are not corrected for the Galactic \nextinction due to the reddening of E(B-V) = 0.13 in the direction of the \nburst (Schlegel et al. 1998).",
  "circularId": 22805,
  "createdOn": 1529504398000,
  "email": "a.breeveld@ucl.ac.uk",
  "subject": "GRB 180620A: Swift/UVOT Detection",
  "submitter": "Alice Breeveld at MSSL-UCL  <a.breeveld@ucl.ac.uk>",
  "eventId": "GRB 180620A"
}