{
  "bibcode": "2016GCN.18922....1O",
  "body": "S. R. Oates (IAA-CSIC/UCL-MSSL) and L. M. Z. Hagen (PSU)\nreport on behalf of the Swift/UVOT team:\n\nThe Swift/UVOT began settled observations of the field of GRB 160121A\n152 s after the BAT trigger (Hagen et al., GCN Circ. 18912).\nNo optical afterglow consistent with the optical position\nreported by MOA (Oates et al., GCN Circ. 18917) is detected\nin 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 first\nfinding chart (FC) exposure and subsequent exposures are:\n\nFilter         T_start(s)   T_stop(s)      Exp(s)         Mag\n\nu_FC               152          401          246         >19.7\nv                  435          830           78         >18.6\nu                  152          918          356         >19.9\nw1                 484          754           58         >18.3\nm2                 459          854           78         >18.4\nw2                 410          805           78         >18.5\n\nThe magnitudes in the table are not corrected for the Galactic extinction\ndue to the reddening of E(B-V) = 0.53 in the direction of the burst\n(Schlafly and Finkbeiner 2011).",
  "circularId": 18922,
  "createdOn": 1453454773000,
  "email": "sro@mssl.ucl.ac.uk",
  "subject": "GRB 160121A: Swift/UVOT Upper Limits",
  "submitter": "Samantha Oates at MSSL  <sro@mssl.ucl.ac.uk>",
  "eventId": "GRB 160121A"
}