TITLE: GCN GRB OBSERVATION REPORT NUMBER: 2600 SUBJECT: GRB 040511: NIR observations with REM DATE: 04/05/15 15:05:40 GMT FROM: Vincenzo Testa at INAF/Astro. Obs. of Rome GRB040511: REM telescope robotic NIR observations. V. Testa, L.A. Antonelli (INAF-OAR), L.Calzoletti (Univ. Roma Sapienza), S. Covino (INAF-OAB), G. Chincarini (Univ. Milano Bicocca), F. M. Zerbi (INAF-OAB), E. Palazzi (IASF-CNR,Bologna), G. Tosti (Univ. Perugia), L. Nicastro (IASF-CNR,Palermo), on behalf of the REM collaboration report: On May 12 the 60cm robotic telescope REM at ESO-La Silla observed the field of GRB040511, that was detected by HETE2 ~12 hours before, during day time at La Silla. The observations were performed with the REMIR near-IR camera during commissioning phase in the wide band filters J,H and Ks in fully automatic mode, following a predefined sequence suited for late grb alerts. Frames obtained in the three filters were co-added together to obtain three images per filter, having total exposure times of 60, 360 and 720s. The comparison with the 2MASS catalog did not reveal evident new sources, with 3 sigma upper limits, on the 720s images, of 18.6 in the J filter, 18.2 in the H filter and 16.6 in the Ks filter. Images were calibrated by using a number of 2MASS stars in the field with high S/N ratio. It was not possible to observe simultaneously in the optical bands because the optical spectrograph ROSS was in maintenance. [GCN OPS NOTE: This Circular was delayed 13 hours until daytime when I could register V.Testa as a new member of the list.]