{
  "bibcode": "2024GCN.35607....1S",
  "subject": "GRB 240118A: Swift/UVOT Upper Limits",
  "submitter": "Mike Siegel at PSU/Swift MOC <mhs18@psu.edu>",
  "eventId": "GRB 240118A",
  "submittedHow": "web",
  "createdOn": 1706031339090,
  "circularId": 35607,
  "body": "M. H. Siegel (PSU) reports on behalf of the Swift/UVOT team:\n\nThe Swift/UVOT began settled observations of the field of GRB 240118A\n96191 s after the LAT trigger (Bissaldi et al., GCN Circ. 35560). No optical afterglow consistent with the\nLAT position or the XRT position (Beardmore et al., GCN Circ. 35587)  is detected in the initial UVOT exposures.\nPreliminary 3-sigma upper limits using the UVOT photometric system\n(Breeveld et al. 2011, AIP Conf. Proc. 1358, 373) for the initial exposures are:\n\nFilter         T_start(s)   T_stop(s)      Exp(s)         Mag\n\nu                96191       103639         3161         >20.8\n\nThe magnitudes in the table are not corrected for the Galactic extinction\ndue to the reddening of E(B-V) = 0.056 in the direction of the burst\n(Schlegel et al. 1998)."
}