Galactic disc column density by maximum likelihood

The method of maximum likelihood is applied to the K dwarf tracer data and galactic-rotation constraint as presented by previous authors, using exactly the same assumptions and data as did those authors. The maximum likelihood estimate of the column density of the galactic disc, Σ0, is 54±8 solar masses pc-2, roughly 1 σ higher than the KG estimate, 46±9 solar masses pc-2. These results depend only very weakly on assumptions about the ellipticity of the halo. (author)