The near-infrared (K-band) Fundamental Plane of elliptical galaxies in the Coma cluster is studied. This is found to have an rms scatter similar to its optical counterpart (0.070dex) but a slightly different shape. The observed scatter in the near-ir FP of ellipticals is mainly due to contributions from the Asymptotic Giant Branch population to their near-ir light or differences in their matter distribution and internal dynamics. However, its slight wavelength-dependence is caused by changes in age, metallicity or a combination of these among the ellipticals. The existence of different M/L ~ M alpha relations at the optical and infrared wavelengths indicates that changes in both luminous-to-dark matter distribution and age (stellar population) or metallicity among the ellipticals are the main parameters responsible for this correlation.
Untangling Coma Berenices: A New Vision of an Old Cluster
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