The SAMI Galaxy Survey: mass-kinematics scaling relations

We use data from the Sydney-AAO Multi-object Integral-field spectroscopy (SAMI) Galaxy Survey to study the dynamical scaling relation between galaxy stellar massM* and the general kinematic parameter S-K = root KVrot2 + sigma(2) that combines rotation velocity V-rot and velocity dispersion s. We show that the logM* -logSK relation: (1) is linear above limits set by properties of the samples and observations; (2) has slightly different slope when derived from stellar or gas kinematic measurements; (3) applies to both early-type and late-type galaxies and has smaller scatter than either the Tully-Fisher relation (logM(*) -log V-rot) for late types or the Faber-Jackson relation (logM(*) - log s) for early types; and (4) has scatter that is only weakly sensitive to the value of K, with minimum scatter for K in the range 0.4 and 0.7. We compare SK to the aperture second moment (the 'aperture velocity dispersion') measured from the integrated spectrum within a 3-arcsecond radius aperture (sigma(3)). We find that while SK and sigma(3) are in general tightly correlated, the logM(*) -log SK relation has less scatter than the logM(*)-log sigma(3) relation.