GCN Circular 22666
P. Schady and T.-W. Chen (both MPE Garching) report: We re-observed the field of GRB 180418A (Swift trigger 826428; D'Elia et al., GCN #22646) simultaneously in g'r'i'z'JHK with GROND (Greiner et al. 2008, PASP 120, 405) on 20th April, at a mid-time of 02UT. Observations were performed at an average seeing of 1.2" and at an average airmass of 1.7. Compared to the previous night of GROND observations (Schady, GCN #22662), the target has decayed by ~0.8dex in the r'-band. Based on around 60 minutes of data, the estimated AB magnitudes from the second epoch of GROND observations are: g' = 24.5 +/- 0.2 mag r' = 24.0 +/- 0.1 mag i' = 23.4 +/- 0.2 mag z' > 23.5 mag J > 21.7 mag H > 21.1 mag K > 19.5 mag Given magnitudes are calibrated against SDSS and 2MASS field stars, and they are not corrected for the expected Galactic foreground extinction corresponding to a reddening of E(B-V)=0.01 mag in the direction of the burst (Schlafly & Finkbeiner 2011). We thank Sam Kim for his excellent support from La Silla.