Towards an unbiased stellar census in open clusters using   multi-wavelength photometry
  We look for very low-mass members in open clusters with different ages placed at different distances. The main goal is to produce a reliable census of low-mass stars for each of the clusters and derive the Initial Mass Function. To achieve this, we combine deep optical and infrared photometry from our own observing runs and from different public databases. We also characterise the individual stellar parameters of our targets. 
F. J. Galindo, D.Barrado and H. Bouy
astro-ph.SR