TITLE: GCN GRB OBSERVATION REPORT NUMBER: 2573 SUBJECT: GRB040422: optical and NIR observations at the VLT DATE: 04/04/22 16:39:15 GMT FROM: Daniele Malesani at SISSA-ISAS,Trieste,Italy D. Malesani (SISSA, Trieste), D. Fugazza, G. Ghirlanda (INAF, Brera), on behalf of a larger international collaboration involved in the Swift mission, report: We observed the error box of the INTEGRAL GRB040422 (Mereghetti et al., GCN 2572), starting 2 hours after the burst. Observations were performed at ESO-Paranal, with an excellent seeing of ~0.5". Optical photometry (in the R and I filters) were acquired with VLT+FORS2, while NIR K-band imaging was performed with VLT+ISAAC. Four exposures were needed to cover the entire INTEGRAL error box in the infrared. We find no obvious sources after comparison of our images with the 2MASS catalog. The limit for the 2MASS is estimated to be K < 14.5 (Skrutskie 2001, AAS #198, 33, 827). We estimate our limiting magnitude to be K = 18.5 based on the 2MASS calibration. Further observations are planned tonight at ESO, in order to search for variable sources. Our images are available upon request. We thank the ESO staff at Paranal, and in particular Nancy Ageorges and Leonardo Vanzi, for quickly performing the observations. This message may be cited.