Optical and near-infrared comparison between mass (M) and mass-to-light ratio (M/L)

Optical (left) and near-infrared (right) comparison between mass (M) and mass-to-light ratio (M/L). The vector shows the evolution of M/L over time. LIRGs (open circles) appear very different in both panels, while non-LIRGs and ellipticals remain the same.