GCN Circular 20299
T. Kruehler, P. Wiseman and J. Greiner (all MPE Garching) report on behalf of the GROND team: We observed the field of GRB 161219B (Swift trigger 727541; D'Ai, GCN #20296) simultaneously in g'r'i'z'JHK with GROND (Greiner et al. 2008, PASP 120, 405) mounted at the 2.2m MPG telescope at the ESO La Silla Observatory (Chile). Observations started at 01:33 UT on 2016-12-20, 6.7 hr after the GRB trigger. They were performed at an average seeing of 1".1, and at an average airmass of 1.3. Based on combined images with 14.5 min of total exposures in g'r'i'z' and 12.0 min in JHK at a mid-time of 01:42 UT on 2016-12-20, we derive the following preliminary magnitudes (all in AB system) for the optical/NIR afterglow (D'Ai et al., GCN 20296). g' = 18.04 +- 0.05 mag r' = 18.08 +- 0.05 mag i' = 17.98 +- 0.05 mag z' = 17.88 +- 0.05 mag J = 17.68 +- 0.05 mag H = 17.57 +- 0.07 mag K = 17.54 +- 0.08 mag Given magnitudes are calibrated against Pan-STARRS/2MASS field stars and are not corrected for the expected Galactic foreground extinction corresponding to a reddening of E_(B-V) = 0.028 mag in the direction of the burst (Schlafly & Finkbeiner 2011). We note the presence of a bright (r=21 mag) and visibly extended galaxy in the Pan-STARRS data at the position of GRB 161219B. This is likely the host galaxy of the GRB and would, if confirmed, indicate a relatively low redshift.