The SAURON project - IV. The mass-to-light ratio, the virial mass estimator and the Fundamental Plane of elliptical and lenticular galaxies

摘要: We investigate the well-known correlations between dynamical mass-to-light ratio M/L and other global observables of elliptical (E) lenticul ar (S0) galaxies. construct twointegral Jeans three-integral Schwarzschild models for a sample 25 E/S0 galaxies with SAURON integral-field stellar kinematics to about one effective (h alf-light) radius Re. They have well-calibrated I-band Hubble Space TelescopeWFPC2 large-field ground-based photometry, accurate surface brightness fluc tuation distances, their observed is consistent an axisymmetric intrinsic sh ape. All these factors result in unprecedented accuracy measurements. find tight correlation form (M/L) = (3.80 ± 0.14) × (σe/200 km s 1 ) 0.84±0.07 (in I-band) measured from luminosity-weighted second moment σe lineof-sight velocity-distribution within The rms scatter our 18%, while inferred � 13%. (M/L)‐σe relation can be included remarkable series galaxy observables. comparison predictions Fundamental Plane (FP), simple virial estimates, shows that ‘tilt ’ FP early-type galaxies, describing deviation relation, almost exclusively due real variation, structural orbital non-homology negligible effect. When photometric parameters are determined ‘classic’ way , using growth curves, large aperture, mass appears reliable estimator central regions safely used where more ‘expensive’ not feasible (e.g. high redshift studies). In this case th e best-fitting has (M/L)vir (5.0±0.1)×Reσ 2 e/(L G), reasonable agreement theoretical predictions. no difference clusters field. (M/L)pop analysis population, indicates median dark matter fractio n 30% total inside Re, broad previous studies, it also initial function varies little among d ifferent Our results suggest variation at constant (M/L)pop, which seems linked dynamics. speculate fast rotating lower matte r fractions than slow generally massive ones. If correct, would connection assembly history halo structure. tightness provides some evidence against cuspy nuclear profiles g alaxies.