Near-Infrared Fundamental Plane of Elliptical Galaxies and Its Evolution

We present the first Fundamental Plane (FP) that has been constructed in the K-band using near—infrared imaging source data. The slope of this IR FP differs systematically both from the optical relation and the virial expectation (assuming homology and constant M/L) in a way that cannot be explained by stellar populations effects alone. We also show observations of the optical and IR FP at higher redshift which demonstrates the same effect. A slight but systematic breakdown of homology along the elliptical galaxy sequence, in addition to stellar populations effects, could explain the FP at all wavelengths.