Dark matter fraction within the effective radius, f_DM(R_e), as a function of the stellar mass for NGC 1277 and NGC 1278 (star symbols). The error bars represent one sigma confidence intervals (that corresponding to NGC 1277 is smaller than the symbol size). Circles correspond to the 103 ATLAS^3D galaxies with good fits in Cappellari et al. (2013a) and the diamond symbols correspond to the data for a sample of 161 passive galaxies from the SAMI Galaxy Survey from Santucci et al. (2022). The colour coding of the symbols indicates the effective radius of the galaxies as shown by the side-bar. The ATLAS^3D data points were derived by merging the galaxy distances from Cappellari et al. (2011), the effective radii and luminosities from Cappellari et al. (2013a), and the f_DM(R_e) and Υ_⋆ values from Cappellari et al. (2013b). The effective radii for the SAMI galaxies were kindly provided by G. Santucci. The green line indicates the M_⋆ − f_DM(R_e) relation derived from JAM models with a fixed cosmologically motivated NFW dark matter halo from Cappellari et al. (2013a). The red line and confidence band correspond to the fit represented in Fig. 7 from Santucci et al. (2022). The black line shows a prediction of the M_⋆ − f_DM(R_e) relation made by combining the dark matter haloes derived from the SHMR from Girelli et al. (2020) and the dark matter halo parametrisation from Child et al. (2018) with the R_e values derived from a linear fit (Eq. (20)) to the size measurements for galaxies with a morphological type T ≤ −1 in Trujillo et al. (2020). The latter relation was calculated assuming a de Vaucouleurs (1948) profile for the stellar component and it is complemented by a one-sigma uncertainty band calculated using a Montecarlo simulation. For the Trujillo et al. (2020) and the Santucci et al. (2022) data and the Girelli et al. (2020) SHMR, the stellar masses were corrected by a factor 0.23 dex to convert the assumed Chabrier (2003) IMF into a Salpeter (1955) one (see Eq. (3) in Sect. 3.2).