Abstract
The initial results of the first large-scale optical-infrared search for brown dwarfs in the Orion star forming region are presented. Optical observations were performed with the Jürgen Stock Schmidt telescope and the QUEST-1 camera at the National Astronomical Observatory of Venezuela, covering an area of 180 deg^2 of which ≈ 32deg^2, that include a portion of OB1a and most of OB1b sub-associations, are studied in this work. R and I band observations were processed with a coadding technique, increasing the limit magnitude to I = 20.5 and R = 21.5 with completitude to I = 19.0 and R = 20.0. Infrared photometry in J, H and K bands was obtained from the Two Micron All Sky Survey data base. Spectroscopic observations of a first sample of candidates was performed with HECTOSPEC and allowed the confirmation of 15 and 9 bonna fide very low mass stars and brown dwarfs respectively.
