{
  "bibcode": "2015GCN.18674....1Y",
  "body": "R. Yates (MPE Garching) , D. A. Kann (TLS Tautenburg), C. Delvaux, and J.\nGreiner (both MPE Garching) report on behalf of the GROND team:\n\nWe observed the field of GRB 151205B (Swift trigger 666378; Marshall et\nal., GCN #18659) simultaneously in g'r'i'z'JHK with GROND (Greiner et al.\n2008, PASP 120, 405) mounted at the 2.2 m MPG telescope at ESO La Silla\nObservatory (Chile).\n\nObservations started at 01:21 UT on 06/12/2015, 3hrs 38 mins after the GRB\ntrigger, and continued for several hours. We obtained a second epoch in\nthe following night.\n\nWe stacked the four deepest images of the first night (exposure times 7920\ns in g'r'i'z' and 6600 s in JHK). They were performed at an average seeing\nof 0\".77 and an average airmass of 1.04. The observations of the second\nnight (exposure times 5760 s in g'r'i'z' and 5400 s in JHK) were obtained\nat 0\".62 seeing and airmass 1.04.\n\nAs there is no XRT detection for this GRB (Kennea et al., GCN #18661;\nD'Avanzo et al., GCN #18672), we performed image subtraction. We note that\nthe g'r'i'z' images do not cover about 25% of the revised BAT error circle\n(Ukwatta et al., GCN #18670) to the north and east. The JHK images cover\nboth the flight and the revised BAT error circle completely.\n\nNo significantly variable sources are detected in any band. The formal\nupper limits (all in AB system) of our images, centered at 0.1939 days\nafter the GRB, are:\n\ng' > 26.5 mag,\nr' > 26.5 mag,\ni' > 25.6 mag,\nz' > 25.0 mag,\nJ > 22.7 mag,\nH > 22.2 mag, and\nK > 21.3 mag.\n\nThe given limits are derived based on calibrating the images against GROND\nzero points and 2MASS field stars and are not corrected for the Galactic\nforeground extinction corresponding to a reddening of E_(B-V)= 0.02 in the\ndirection of the burst (Schlegel et al. 1998).",
  "circularId": 18674,
  "createdOn": 1449612159000,
  "email": "kann@tls-tautenburg.de",
  "subject": "GRB 151205B: Deep GROND Upper limits",
  "submitter": "Alexander Kann at TLS Tautenburg  <kann@tls-tautenburg.de>",
  "eventId": "GRB 151205B"
}