GCN Circular 9408
A. Rossi (Tautenburg), T. Kruehler, J. Greiner and A. Yoldas (all MPE Garching) report on behalf of the GROND team: We observed the field of GRB 090519 (Swift trigger 352648, M. Perri et al., GCN #9400) simultaneously in g'r'i'z'JHK with GROND mounted at the 2.2m ESO/MPI telescope at La Silla Observatory (Chile). Observations started on 19 May 2009 at 23:44 UT, 2.5 h after the burst, under challenging sky conditions with cirrus. We detect the afterglow at a position consistent with the enhanced XRT error circle and NOT (Thoene et al., GCN #9403). With an exposure time of 40min in JHK and 49min in griz, preliminary photometry yields the following AB magnitudes: g =25.0 +-0.4 r =23.5 +-0.2 i =23.5 +-0.3 z >23.6 J >21.9 H >20.7 K >19.9 calibrated using SDSS and 2MASS field stars. The quoted magnitudes are not corrected for the galactic foreground extinction corresponding to a reddening of E_(B-V)=0.04. The large g-i color as compared to r-i indicates that the Lyman break may be located in the g' band. Fitting the SED with Hyper-Z results in a preliminary photometric redshift of z = 3.9+0.4-0.7, assuming no intrinsic extinction.