where A , B , the extrapolated central dispersion σ$_{0}$ and the projected scale length R$_{σ}$ are the fitting parameters. The fit yields R$_{σ}$ = 1 . 16 ± 0 . 29 kpc and σ$_{0}$ = 59 . 5 ± 8 . 4 km s − $^{1}$, which will provide a point of comparison for our results in § 6. Note that we do not attempt to model the physical processes which may be responsible for the σ − drop, but we do determine structural parameters and effective M/L ratios for the bulge to account for the σ − drop. NGC 6503 was the first galaxy shown to have a σ − drop. A growing body of data suggests that σ − drops are found in numerous spiral galaxies (M´ arquez et al. 2003; Comer´ on et al. 2008; de Lorenzo-C´ aceres et al. 2008), although Kovela et al. (2008) argue that some σ − drops are observational artifacts. BG97 suggest that the σ − drop is due to a small central, possibly star forming component capable of continually cooling the centre. A physical explanation for σ − drops is proposed by Wozniak et al. (2003) and Wozniak & Champavert (2006), who argue that the presence of dynamically cold gas funnelling into the centre is responsible for forming dynamically cold stars that dominate the observed LOS kinematics. Comer´ on et al. (2008)’s sample of σ − drop galaxies correlates with higher incidences of nuclear dust spirals, H α rings and Seyfert fraction, which would be consistent with a cold star-forming compo- nent in the centre due to gas inflow. Meanwhile, de Lorenzo-C´ aceres et al. (2008) suggest that inner nuclear bars may be responsible for at least some of the σ − drops found in the literature. We test three different ways to fit the SB profile: (i) assuming an inner truncated disc; (ii) assuming an exponential disc with an inner truncated light profile to model simply the effect of dust extinction (a full dust model is outside the scope of this work); and (iii) fitting only the inner ( R ≲ 0 . 1 kpc) and outer ( R > 2 kpc) points to account for the true disc being external to the Type II hump. Furthermore, we test two ways to model the rotation: (i) we fit the gas rotation by assuming that it equals the circular velocity; and (ii) we fit the stellar rotation by simulating the LOS observations of the inclined disc. Simulating observations along a line of sight is particularly important for stellar kinematic measurements because of the non-negligible scale height of the stellar disc, which leads to integration effects as the line of sight passes through regions of the disc that are not in the plane. This effect is less important for the gas disc, which is expected to have a small scale height. These tests are accounted for by four different scenarios. In scenario K (for Kormendy), we fit the full surface brightness with an inner truncated Kormendy disc, and we fit the stellar rotation curve. In KL (Kormendy light), we fit the surface brightness using an inner truncated light profile atop an exponential disc to account for dust extinction, and fit the 8 2.4. Four scenarios to test