TITLE: GCN CIRCULAR NUMBER: 9319 SUBJECT: GRB 090427: GROND observations DATE: 09/05/04 00:07:14 GMT FROM: Felipe Olivares Estay at MPE F. Olivares, T. Kruehler, J. Greiner (all MPE Garching) report on behalf of the GROND team: We observed the central area of the error box of GRB 090427 localized by the IPN (Pal'shin et al., GCN #9277) simultaneously in g'r'i'z'JHK with GROND mounted at the 2.2m ESO/MPI telescope at La Silla Observatory (Chile). Three adjacent pointings centered at RA = 15,43,31.0 Decl. = -13,40,00 RA = 15,43,43.4 Decl. = -13,30,00 (center of IPN box) RA = 15,43,55.0 Decl. = -13,20,00 have been observed with our 10x10 arcmin (in JHK) and 5.4x5.4 arcmin (g'r'i'z') field-of-view, thus covering about 27% and 8% of the full error box respectively (see sketch at http://www.mpe.mpg.de/~jcg/grb090427.html). Observations started on 29 Apr. 2009 at 06:20 UT, 30.9 h after the burst, and consisted, for each of the three fields, of a set of images with a total integration time of 8 min in JHK and 7.7 min in g'r'i'z'. A second epoch of all three fields was obtained on 30 Apr. 2009 starting at 05:18 UT. Image subtraction of the two epochs does not reveal a variable source in any of the three fields, down to limiting magnitudes (all in AB system) of g' > 23.9 r' > 23.8 i' > 23.5 z' > 23.2 J > 22.2 H > 21.7 K > 20.6 These magnitudes have been obtained using 2MASS field stars and the GROND zeropoints as reference.