Deep optical and near infrared observations in ELAIS areas

We present deep optical and near infrared imaging over half square degree of sky in the centres of the ELAIS regions N1 and N2 and coincident with deep XMM/Chandra observations. The data have been obtained with the Wide Field Camera (WFC) and the Cambridge InfraRed Survey Instrument (CIRSI) both at the Isaac Newton Telescope (Observatorio del Roque de los Muchachos, Canary Islands). Limiting magnitudes achieved are g'=26.7, r'=26.2, i'=25.0 and H=20.2 (3 sigma). These data have been used to identify the faint optical counterparts of the Infrared Space Observatory (ISO), radio and X-ray sources in these areas.