2012MNRAS.423.2726G

We measure the shape of the velocity ellipsoid in two late-type spiral galaxies (Hubble types Sc and Scd) and combine these results with our previous analyses of six early-type spirals (Sa to Sbc) to probe the relation between galaxy morphology and the ratio of the vertical and radial dispersions. We confirm at much higher significance (99.9 per cent) our prior detection of a tight correlation between these quantities. We explore the trends of the magnitude and shape of the velocity ellipsoid axes with galaxy properties (colour, gas surface mass density and spiral arm structure). The observed relationships allow for an observational identification of the radial and vertical disc heating agents in external disc galaxies.

Based on observations made with ESO Telescopes at the La Silla Observatory under programmes 074.B-0550(A) and 078.B-0152(A).