The Influence of Bulge Profile Shapes on Claims for a Scale-free Hubble Sequence for Spiral Galaxies

Graham, A. W.; Prieto, M.
Referencia bibliográfica

The Astrophysical Journal, Volume 524, Issue 1, pp. L23-L26.

Fecha de publicación:
10
1999
Número de autores
2
Número de autores del IAC
1
Número de citas
25
Número de citas referidas
22
Descripción
We investigate recent claims that the Hubble sequence of spiral galaxies is scale-free. Fundamental to this investigation is the fact that within the photometric data of 86 spiral galaxies from de Jong & van der Kruit-from which these claims were made-a trend exists between morphological type and bulge profile shape. While late-type spiral bulges are described by an exponential luminosity profile, the early-type spiral bulges are better described by an r^1/2 or r^1/4 law. Taking the scale lengths from the best-fitting surface brightness profile models (i.e., either using exponential, r^1/2, or r^1/4 law profile parameters), we show that in all six passbands used (BVRIHK), the early-type spiral galaxies have a larger r_e/h ratio than late-type spiral galaxies. In contrast to this, fitting an exponential profile to the bulges of all spiral galaxies results in the mean r_e/h ratio for the early-type spiral galaxies actually being smaller than the mean r_e/h ratio for the late-type spiral galaxies (at the 3 sigma significance level using K-band data).