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
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).