Tully-Fisher relation (TFR) for LTGs. We compute the rotational gas velocity v_rot for the NBCS and CS (black and blue contour lines) using the gas velocity dispersion σ_gas (see Sect. 4.3.1). For the DPS, we use the σ_single of the single Gaussian approximation in the top panel. In the second panel, we show the TFR for the close and far peak-components of the DPS (see Sect. 4.3.1). The stellar masses are computed by Kauffmann et al. (2003). We show the best fit computed by Avila-Reese et al. (2008) as a dashed line.