A linear near-IR Tully-Fisher relation for giant and dwarf late-type galaxies

We present the near-IR (K'-band, i.e.: lambda = 2.1 mu m) Tully-Fisher (TF) relation for a sample of 50 giant and dwarf late-type galaxies, selected f rom the Virgo Cluster Catalogue. We find that L proportional to V-Max(4) al ong a range of 8 K'-mag for galaxies with different Hubble types (from Sa t o Im-BCD), phenomenologies, structures, star-formation histories, masses, d ark-to-luminous mass ratios, metallicities and, perhaps, ages. The linearit y of the near-IR TF relation is in contrast with recent determinations of t he optical TF relations for samples of extreme late-type and dwarf galaxies . The near-IR TF law is in agreement both with the expectation from the Fun damental Plane for disk systems and with the scenario of self-regulating st ar-formation in disks. The previous results suggest that the TF relation re flects the connection between the structural/dynamical properties and the s tar-formation process of both giant and dwarf late-type galaxies, through a gas supply for star-formation regulated by the gravitational potential of the galaxy.