{
  "bibcode": "2025GCN.43145....1O",
  "subject": "GRB 251215A: Swift/UVOT Upper LImits",
  "eventId": "GRB 251215A",
  "createdOn": 1765911126395,
  "body": "S. R. Oates (Lancaster U.) reports on behalf of the Swift/UVOT team:\n\nThe Swift/UVOT began settled observations of the field of GRB 251215A\n32 ks after the Fermi/GBM trigger (Fermi GBM team, GCN Circ. 43104).\nNo optical afterglow is found in the initial UVOT exposures. The UVOT\nexposures include the positions of XRT sources 2, 5, 6 and 8\n(Osborne et al., GCN 43137). The positions of XRT sources 2, 6, and 8\nare consistent with known USNO-B1 sources. No optical source is found\nconsistent with XRT source 5.\n\nPreliminary 3-sigma upper limits using the UVOT photometric system\n(Breeveld et al. 2011, AIP Conf. Proc. 1358, 373) for the first\nfinding chart (FC) exposure and subsequent exposures are:\n\nFilter   T_start(s)   T_stop(s)      Exp(s)     Mag/3sigUL\nwhite    31995          49531         4297       >22.4\n\n\nThe magnitudes in the table are not corrected for the Galactic extinction\ndue to the significant reddening of E(B-V) = 0.87 in the direction of the\nburst (Schlegel et al. 1998).\n\n",
  "submitter": "S. R. Oates at Lancaster University <samantha.oates@ucl.ac.uk>",
  "submittedHow": "email",
  "circularId": 43145
}