{
  "bibcode": "2014GCN.16666....1K",
  "body": "D. A. Kann (TLS Tautenburg), C. Delvaux, and J. Greiner (both MPE\nGarching) report on behalf of the GROND team:\n\nWe observed the field of GRB 140801A (Fermi trigger 428612396; Pelassa,\nGCN #16658) simultaneously in g'r'i'z'JHK with GROND (Greiner et al. 2008,\nPASP 120, 405) mounted at the 2.2 m MPG telescope at ESO La Silla\nObservatory (Chile).\n\nObservations started at 09:43 UT on 2014-08-02, 0.61 days after the GRB\ntrigger. They were performed at an average seeing of 1\".5 and at an\naverage airmass of 2.1.\n\nBased on images with exposure times of 1584 s in g'r'i'z', we detect the\noptical afterglow at the MASTER position reported by Gorbovskoy et al.\n(GCN #16653) at the following AB magnitudes:\n\ng' = 22.4 +/- 0.1 mag,\nr' = 21.9 +/- 0.1 mag,\ni' = 21.8 +/- 0.1 mag, and\nz' = 21.2 +/- 0.2 mag.\n\nObservations taken a day later show the afterglow to have decayed by about\n0.75 magnitudes. The afterglow continues to decay with a slope of ~0.9 in\ncomparison to the magnitudes given by Xu et al. (GCN #16656) and Moskvitin\net al. (GCN #16663).\n\nThe given magnitudes are derived based on calibrating the images against\nthe GROND zeropoints and are not corrected for the Galactic foreground\nextinction corresponding to a reddening of E_(B-V) = 0.23 in the direction\nof the burst (Schlegel et al. 1998).",
  "circularId": 16666,
  "createdOn": 1407104091000,
  "email": "kann@tls-tautenburg.de",
  "subject": "GRB 140801A: GROND Afterglow detection, unbroken decay",
  "submitter": "Alexander Kann at TLS Tautenburg  <kann@tls-tautenburg.de>",
  "eventId": "GRB 140801A"
}