International Gemini Observatory/NOIRLab/NSF/AURA
Comparison of optical (CaT) and near-IR (CO 2.29μm) σ◦
For luminous infrared galaxy (LIRG) mergers (left), velocity dispersion measured with CO (CO σ0) is significantly lower than that measured with the Calcium II Triplet (CaT σ0). For non-LIRG mergers and normal elliptical galaxies (middle and right), there is no meaningful difference between the two techniques.
