{
  "bibcode": "2014GCN.15665....1T",
  "body": "M. Tanga (MPE Garching), S. Klose (TLS Tautenburg), and J. Greiner (MPE \nGarching) report on behalf of the GROND team:\n\nWe observed the field of GRB 140102A (Hagen et al., GCN 15653) \nsimultaneously in g'r'i'z'JHK with GROND (Greiner et al. 2008, PASP 120, \n405) mounted at the 2.2m MPG telescope at La Silla Observatory (Chile).\n\nObservations started at 07:51 UT on Jan 03, about 10.5 hrs after the GRB \ntrigger. The afterglow discovered by Hagen et al. (see also Gorosabel et \nal., GCN 15658; Xu et al., GCN 15655) is detected in all optical bands. At \na mean time of 08:19 UT, we measure the following preliminary AB \nmagnitudes:\n\ng'= 21.6 +/- 0.1,\nr'= 21.4 +/- 0.1,\ni'= 20.9 +/- 0.1,\nz'= 21.0 +/- 0.1,\nJ = 20.7 +/- 0.3,\nH = 20.6 +/- 0.4,\nK > 19.3,\n\ncalibrated against SDSS and 2MASS field stars.\n\nAfter correcting for a Galactic reddening of E(B-V)=0.03 mag (Schlegel et \nal. 1998), the spectral slope defined by g'r'z'JH is ~ 0.7, with no \nevidence for host extinction.\n\nThe SED fit shows a slight excess in i'-band flux. It could be due to \nemission line(s) from the underlying host, though we cannot say anything \nabout an underlying galaxy due to the bad image quality (FWHM ~ 2.5\"). We \nnote, however, the presence of a galaxy just 4\" East of the afterglow.",
  "circularId": 15665,
  "createdOn": 1388761419000,
  "email": "klose@tls-tautenburg.de",
  "subject": "GRB 140102A: GROND observations",
  "submitter": "Sylvio Klose at TLS Tautenburg  <klose@tls-tautenburg.de>",
  "eventId": "GRB 140102A"
}