Dark matter in early – type galaxies : dynamical modelling of IC 1459 , IC 3370 , NGC 3379 and NGC 4105

We analyse long–slit spectra of four early–type galaxies which extend from ∼ 1 to ∼ 3 effective radii: IC 1459, IC 3370, NGC 3379 and NGC 4105. We have extracted the full line–of–sight velocity distribution (in the case of NGC 3379 we also used data from the literature) which we model using the two–integral approach. Using two–integral modelling we find no strong evidence for dark haloes, but the fits suggest that three– integral modelling is necessary. We also find that the inferred constant mass–to–light ratio in all four cases is typical for early–type galaxies. Finally, we also discuss the constraints on the mass–to–light ratio which can be obtained using X–ray haloes in the case of IC 1459, NGC 3379 and NGC 4105 and compare the estimated values with the predictions from the dynamical modelling.