{
  "bibcode": "2020GCN.28501....1D",
  "body": "A. de Ugarte Postigo (HETH/IAA-CSIC, DARK/NBI), D. A. Kann, C. C. Thoene,\nM. Blazek, J. F. Agui Fernandez (all HETH/IAA-CSIC), and F. Aceituno \n(IAA-CSIC) report:\n\nWe observed the location of the Swift GRB 200925B (Cenko et al., GCN \n#28499) with the 1.5m telescope of the Observatorio Sierra Nevada, in \nGranada, Spain. We obtained a 300 s image each in the BVRc bands and \nmultiple 100 s images in Ic, beginning 2020-09-25 22:27:07 UT.\n\nWe detect a source in all filters at\n\nRA (J2000) = 16:27:08.50\nDec. (J2000) = +78:23:24.9\n\nwith an error of 0\".5, within the UVOT-enhanced XRT position (Evans, GCN \n#28500). We note this source is also clearly detected in the initial \nSwift UVOT white finding chart, at a significantly brighter magnitude \nrelative to the nearby field star.\n\nThis strongly suggests the source is fading and is therefore the \nafterglow of GRB 200925B.\n\nAt 0.034294 days after the GRB, we measure r' = 19.46 +/- 0.1 (AB \nmagnitude) vs. nearby SDSS field stars.\n\n[GCN OPS NOTE(26Sep20): Per the author's request: in the Title the \"25A\" was changed to \"25B\",\nthe affiliation of A. de Ugarte Postigo is \"*-CSIC\" not \"*-CSIS\",\n\"Thoene\" not \"Thone\", and in the first sentence, the \"200906A\" should be \"200925B\".]",
  "circularId": 28501,
  "createdOn": 1601075667000,
  "email": "kann@iaa.es",
  "subject": "GRB 200925B: OSN Afterglow Candidate Discovery",
  "submitter": "Alexander Kann at IAA-CSIC  <kann@iaa.es>",
  "eventId": "GRB 200925B"
}