TITLE: GCN CIRCULAR NUMBER: 12568 SUBJECT: GRB 111117A: GROND observations DATE: 11/11/18 11:02:44 GMT FROM: Alexander Kann at TLS Tautenburg S. Schmidl, A. Rossi, D. A. Kann, (all TLS Tautenburg) and J. Greiner (MPE Garching) report on behalf of the GROND team: We observed the field of GRB 111117A (Swift trigger #507901, Mangano et al., GCN 12559) simultaneously in g'r'i'z'JHK with GROND (Greiner et al. 2008, PASP 120, 405) mounted at the 2.2 m MPI/ESO telescope at La Silla Observatory (Chile). Observations started at 02:01 UT on November 18, 13.8 hr after the GRB trigger. They were performed at an average seeing of 1".8 and an average airmass of 1.7 . We detect the afterglow/host candidate that was reported by Andersen et al. (GCN 12563, R = 23.1 ± 0.3), Fong et al. (GCN 12566, r = 23.9 ± 0.15) and Cucchiara et al. (GCN 12567, r' = 23.99 ± 0.11) in the g' and r' band. Based on the first 75 min of total exposures in g'r'i'z' and 60 min in JHK, we estimate preliminary magnitudes (all in AB system) of g' = 24.08 ± 0.15, r' = 24.08 ± 0.16, i' > 23.9, z' > 23.4, J > 21.7, H > 21.3 and K > 19.5. Our r'-band magnitude is in agreement with Fong et al. and Cucchiara et al. Magnitudes are calibrated against SDSS as well as 2MASS field stars and are not corrected for the expected Galactic foreground extinction corresponding to a reddening of E_(B-V)=0.03 mag in the direction of the burst (Schlegel et al. 1998).