Do Elliptical Galaxies Have r1/4 -Law Brightness Profiles?
De Vaucouleurs’ (1948, 1953) r1/4 law fits bright elliptical galaxies reasonably well except where tidal effects are important. We do not attach physical significance to this choice of function, although Binney (1982c) and Bertin & Stiavelli (1984, 1989) find reasonable distribution functions whose density profiles are similar to it. The r1/4 law is a convenient parameterization that extracts all of the scaling information that we are entitled to derive, given the similarity of profiles to power laws (Kormendy 1980, K82). But how well does it work? No definitive study has been published. Based on large photometric surveys, Michard (1985), Djorgovski et al. (1985), Djorgovski (1985), Schombert (1986, 1987), Kodaira et al. (1986), Jedrzejewski (1987b), Capaccioli et al. (1988), and de Carvalho & da Costa (1988) conclude that ellipticals have a wide variety of profile shapes. A corollary is that fitting functions with two scale parameters but no shape parameter are not particularly useful
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- Do Elliptical Galaxies Have r1/4 -Law Brightness Profiles?
