The EFIGI catalogue of 4458 nearby galaxies with morphology II. Statistical properties along the Hubble sequence

Valérie de Lapparent (1) , Anthony Baillard (1) , Emmanuel Bertin (1)

1 IAP - Institut d'Astrophysique de Paris

The EFIGI catalogue of 4458 galaxies provides a reference database of the morphological properties of nearby galaxies, with 16 shape attributes describing their various dynamical components, their texture and environment, and with a dense sampling of all Hubble types. This catalogue allows us to derive a quantitative description of the Hubble Sequence in terms of the specific morphological features of the various types. The variations of the EFIGI morphological attributes with type confirm that the Hubble sequence is a decreasing sequence of bulge-to-total ratio and an increasing sequence of disk contribution to the total flux. There is nevertheless a large dispersion of approximately 5 types for a given bulge-to-total ratio, due to the fact that the Hubble sequence is primarily based on the strength and pitch angle of the spiral arms, independently from the bulge-to-total ratio. The grand spiral design is also related to a steep decrease in visible dust from types Sb to Sbc-Sc. In contrast, the scattered and giant HII regions show different strength variation patterns; hence, they do not appear to directly participate into the establishment of the visual Hubble sequence. The distortions from a symmetric profile also incidentally increase along the sequence. Bars and inner rings are frequent and occur in 41% and 25% of disk galaxies resp. Outer rings are twice less frequent than inner rings, and outer pseudo-rings occur in 11% of barred galaxies. Finally, we find a smooth decrease in mean surface brightness and intrinsic size along the Hubble sequence. The largest galaxies are cD, Ellipticals and Sab-Sbc spirals, whereas Sd and later spirals are nearly twice smaller. S0 are intermediate in size, and Im, cE and dE are confirmed as small objects. Dwarf spiral galaxies of type Sa to Scd are rare in the EFIGI catalogue, we only find 2 such objects.

Mots clés: Astronomical data bases; Astronomical databases: miscellaneous; Catalogs; Surveys; Galaxies: fundamental parameters; Galaxies: elliptical and lenticular; cD; Galaxies: spiral; Galaxies: dwarf; Galaxies: peculiar; Galaxies: interactions; Galaxies: bulges; Galaxies: statistics; Galaxies: photometry; Galaxies: star formation; Galaxies: structure

Domaines: Cosmologie et astrophysique extra-galactique [astro-ph.CO]; Cosmologie et astrophysique extra-galactique [astro-ph.CO]

Valérie de Lapparent, Anthony Baillard, Emmanuel Bertin. The EFIGI catalogue of 4458 nearby galaxies with morphology II. Statistical properties along the Hubble sequence. Astronomy and Astrophysics - A&A, 2011, 532, pp.A75. ⟨10.1051/0004-6361/201016424⟩. ⟨hal-00582553⟩