We have obtained the best fit to the light profiles of a luminosity- limited sample of elliptical and S0 galaxies with a power law r^1/n^, letting the exponent remain free rather than keeping it fixed at 1/n = 1/4 as in the well-known de Vaucouleurs formula. The introduction of a free parameter in the fitting formula (ranging from n = 0.5 for (r_e_) = 0.3 kpc to n = 16 for (r_e_) = 25 kpc) is justified by the existence of a good correlation between n and the global galaxian parameters, such as total luminosity and scale-radius. This result seems to be in line with the segregation of properties between the `ordinary' and `bright' families of early-type galaxies, and has consequences for the claimed independence of the shape of galaxy profiles with respect to the Fundamental Plane parameters.
On the shape of the light profiles of Early Type galaxies
D'ONOFRIO, MAURO
1993
Abstract
We have obtained the best fit to the light profiles of a luminosity- limited sample of elliptical and S0 galaxies with a power law r^1/n^, letting the exponent remain free rather than keeping it fixed at 1/n = 1/4 as in the well-known de Vaucouleurs formula. The introduction of a free parameter in the fitting formula (ranging from n = 0.5 for (r_e_) = 0.3 kpc to n = 16 for (r_e_) = 25 kpc) is justified by the existence of a good correlation between n and the global galaxian parameters, such as total luminosity and scale-radius. This result seems to be in line with the segregation of properties between the `ordinary' and `bright' families of early-type galaxies, and has consequences for the claimed independence of the shape of galaxy profiles with respect to the Fundamental Plane parameters.Pubblicazioni consigliate
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