{
  "bibcode": "2015GCN.18277....1S",
  "body": "S. Schmidl (TLS Tautenburg), F. Knust, and J. Greiner (both MPE Garching)\nreport on behalf of the GROND team:\n\nWe observed the field of GRB 150910A (SWIFT trigger 655097; Pagani et al,\nGCN 18264) simultaneously in g'r'i'z'JHK with GROND (Greiner et al. 2008,\nPASP 120, 405) mounted at the 2.2m MPG telescope at ESO La Silla\nObservatory (Chile).\n\nObservations started on September 11, 2015, at 05:08 UT, 20.1 hrs after the\nGRB trigger. They were performed at an average seeing of 2.8\" and at an\naverage airmass of 2.2.\n\nWe clearly detect the optical afterglow reported by Pagani et al. (GCN\n18264), Zheng & Filippenko (GCN 18265), Dichiara et al. (GCN 18266),\nKuroda et al. (GCN 18267), Xu et al. (GCN 18269), de Ugarte Postigo et al.\n(GCN 18274) and Moskvitin et al (GCN 18275).\n\nBased on total exposures of 7.7 minutes in g'r'i'z'and 4.0 minutes in\nJHK, at a midtime of 20.8 hrs after the burst, we measure the following\npreliminary magnitudes (AB magnitude system):\n\ng' = 21.5 +/- 0.2 mag,\nr' = 21.2 +/- 0.2 mag,\ni' = 21.0 +/- 0.2 mag,\nz' = 20.8 +/- 0.2 mag,\nJ  > 19.8 mag,\nH  > 19.3 mag, and\nK  > 18.1 mag.\n\nGiven magnitudes and upper limits are calibrated against SDSS as well as\n2MASS field stars and are not corrected for the expected Galactic\nforeground extinction corresponding to a reddening of E_(B-V) = 0.05 mag\nin the direction of the burst (Schlegel et al. 1998).",
  "circularId": 18277,
  "createdOn": 1441960245000,
  "email": "schmidl@tls-tautenburg.de",
  "subject": "GRB 150910A: GROND observation of the afterglow",
  "submitter": "Sebastian Schmidl at TLS Tautenburg  <schmidl@tls-tautenburg.de>",
  "eventId": "GRB 150910A"
}