[F98] omd 5 , the SIMBAD biblio

By using dark nebulae as opaque outer screens, the luminosity function of white dwarfs and M dwarfs has been studied. High-extinction areas towards the Orion A, Serpens and ρ Oph cloud complexes were observed, covering a volume corresponding to 464pc³ in the solar neighbourhood, complete to M_V∼16.5. Foreground stars were selected by VRI photometry and photometric parallaxes. The resulting foreground sample consists of 21 M dwarfs and 7 white dwarfs. The derived M-dwarf luminosity function is consistent with previous studies, showing no substantial upturn beyond M_V=16. The 7 white dwarfs imply a local density of 0.013(±0.005)M_☉/pc³ (∼15% of the dynamical mass in the solar neighbourhood) supporting other recent results but obtained with a completely different method. For the clouds, foreground-star data were used to derive independent cloud distances, while the background stars and a simple model of the Milky Way gave reliable cloud extinctions.