R Yates, T-W Chen, and J Greiner (all MPE Garching) report on behalf of
the GROND team:
We observed the field of GRB 160411A (Swift trigger 682339; Page et al.,
GCN #19279) 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
Observations started at 09:14 UT on 11-04-2016, 7 hr 45 min after the GRB
trigger. They were performed at an average seeing of 1.9" in the r'-band
and at an average airmass of 1.8.
Based on the first 49 min of total exposures, we do not detect a source
within the 4.0" Swift-XRT error circle reported by Perri et al. (GCN
#19281) down to (all in the AB system):
g' > 23.7 mag,
r' > 23.9 mag,
i' > 23.1 mag,
z' > 22.9 mag,
J > 21.3 mag,
H > 20.8 mag, and
K > 19.9 mag.
The given limits are derived based on calibrating the images against GROND
zeropoints and 2MASS field stars and are not corrected for the Galactic
foreground extinction corresponding to a reddening of E_(B-V)=0.02 mag in
the direction of the burst (Schlafly & Finkbeiner 2011).