TITLE: GCN CIRCULAR NUMBER: 19375 SUBJECT: GRB 160501A: GROND Upper limits DATE: 16/05/02 10:01:04 GMT FROM: Fabian Knust at MPE/GROND J. Bodensteiner, F. Knust, T. Schweyer , J. Greiner (all MPE Garching) report on behalf of the GROND team: We observed the field of GRB 160501A (Swift trigger 684679; Cummings et al., GCN #19365) simultaneously in g'r'i'z'JHK with GROND (Greiner et al. 2008, PASP 120, 405) mounted at the 2.2 m MPG telescope at ESO La Silla Observatory (Chile). Observations started at 07:15 UT on 2016-05-01, 6h 35min after the GRB trigger. They were performed at an average seeing of 1.3" and at an average airmass of 1.09. We do not detect a source within the Swift-XRT error circle reported by Evans et al. (GCN #19369) down to g' > 24.8 mag, r' > 24.5 mag, i' > 23.8 mag, z' > 23.9 mag, J > 21.1 mag, H > 20.7 mag, and K > 19.1 mag. (all in AB). The given limits are derived based on calibration against GROND zeropoints and 2MASS field stars and are not corrected for the Galactic foreground extinction corresponding to a reddening of E_(B-V)= 0.18 mag in the direction of the burst (Schlegel et al. 1998).