{
  "bibcode": "2015GCN.17495....1N",
  "body": "A. Nicuesa Guelbenzu (TLS Tautenburg), P. Wiseman (MPE Garching), and J.\nGreiner (MPE Garching) report:\n\nWe observed the field of GRB 150222A (Swift trigger 632180; Bernardini et\nal., GCN 17486) simultaneously in g'r'i'z'JHK with GROND (Greiner et al.\n2008, PASP 120, 405) mounted at the 2.2m MPG telescope at ESO La Silla\nObservatory (Chile).\n\nObservations started at 03:39:15 UT on February 23, about 10 hours after\nthe GRB trigger. Inside the enhanced X-ray error circle (Beardmore et al.,\nGCN 17494) we detect a faint source at coordinates RA, DEC (J2000) =\n13:15:08.75, -12:09:06.2 with an error of 0\".5.\n\nAt a mean time of February 23, at 04:39:07 UT, we measure the following\npreliminary AB magnitude:\n\n\ng' = 24.8 +/- 0.2.\nr' = 24.6 +/- 0.3.\n\nAt present we cannot decide if this is the afterglow. Observations are\nongoing.\n\nMagnitudes are calibrated against GROND zeropoints (g'r'i'z')\nand are not corrected for the Galactic extinction\nin the direction of the burst.",
  "circularId": 17495,
  "createdOn": 1424675701000,
  "email": "ana@tls-tautenburg.de",
  "subject": "GRB 150222A: GROND optical afterglow candidate",
  "submitter": "Ana Nicuesa at TLS Tautenburg  <ana@tls-tautenburg.de>",
  "eventId": "GRB 150222A"
}