{
  "bibcode": "2015GCN.18224....1K",
  "body": "Paul Kuin, Massimiliano de Pasquale (UCL/MSSL), Daniele\nMalesani (DARK/NBI) and Peter Brown (TAMU) report on\nbehalf of the Swift UVOT team:\n\nThe light curve from GRB 150821A as observed by Swift/UVOT has\nbeen monitored continuously since its discovery, up to about\n300 ks in all seven filters, and in u, v and white since.\n\nThe GRB brightness decreased as a straight power law with\nindex -1.32 (+0.06/-0.05) until about 10 ks. At 100 ks\nthere was a clear flattening in the light curve, and around\n250 ks a slight brightening may have taken place, but the\nbrightness could also be flat within our observational errors.\nData taken at 835 ks are consistent with a flat or slightly\ndecreasing brightness.\n\nThe summed 5 ks image in the white band from 300 - 800 ks\nshows a nearby extended object to the north-west with\nwhite = 22.01 +/- 0.17 mag, slightly brighter than the GRB at\nabout 10\" distance which currently is at white=23.2 +/- 0.7\nmagnitudes, and is located about 5\" from the edge of the\nnearby object.\n\nAt this time it is unclear whether the observed flattening is\ndue to the host galaxy (hosts at this distance have typically\na size of 1\" only) or are the emergence of a supernova\ncontribution to the afterglow. At the redshift of z = 0.755\n(D'Elia et al., GCN Circ. 18187), the observed brightness\nwould imply a SN significantly brighter than those typically\nassociated with GRBs.\n\nFurther ground observations are encouraged.",
  "circularId": 18224,
  "createdOn": 1441121639000,
  "email": "npkuin@gmail.com",
  "subject": "GRB 150821A: Flattening in the UVOT light curve",
  "submitter": "Paul Kuin at MSSL  <npkuin@gmail.com>",
  "eventId": "GRB 150821A"
}