Dark matter measurements combining stellar and HI kinematics: 30 1-σ outliers with low dark matter content at 5R_e

We construct the Schwarzschild dynamical models for 11 early-type galaxies with the SAURON and Mitchell stellar IFUs out to 2-4 R_e, and construct dynamical models with combined stellar and HI kinematics for a subsample of 4 galaxies with HI velocity fields out to 10 R_e obtained from the Westerbork Synthesis Radio Telescope, thus robustly obtaining the dark matter content out to large radii for these galaxies. Adopting a generalised-NFW dark matter profile, we measure an NFW-like density cusp in the dark matter inner slopes for all sample galaxies, with a mean value of 1.00±0.04 (rms scatter 0.15). The mean dark matter fraction for the sample is 0.2 within 1 R_e, and increases to 0.4 at 2 R_e, and 0.6 at 5 R_e. The dark matter fractions within 1 R_e of these galaxies are systematically lower than the predictions of both the TNG-100 and EAGLE simulations. For the dark matter fractions within 2 R_e and 5 R_e, 40 are 1-σ consistent with either the TNG-100 or the EAGLE predictions, while the remaining 60 Combined with 36 galaxies with dark matter fractions measured out to 5 R_e in the literature, about 10 3-σ region of the TNG-100 or EAGLE predictions.