The inner mass distribution of late-type spiral galaxies from <monospace>SAURON</monospace> stellar kinematic maps

We infer the central mass distributions within 0.4-1.2 disc scalelengths of 18 late-type spiral galaxies using two different dynamical modelling approaches - the asymmetric drift correction (ADC) and axisymmetric Jeans anisotropic multi-Gaussian expansion (JAM) model. ADC adopts a thin-disc assumption, whereas JAM does a full line-of-sight velocity integration. We use stellar kinematics maps obtained with the integral-field spectrograph {SAURON} to derive the corresponding circular velocity curves from the two models. To find their best-fitting values, we apply the Markov Chain Monte Carlo (MCMC) method. ADC and JAM modelling approaches are consistent within 5 per cent uncertainty when the ordered motions are significant comparable to the random motions, I.e. overline{v_{φ }}/σ _R is locally greater than 1.5. Below this value, the ratio v_{c, JAM}/v_{c, ADC} gradually increases with decreasing overline{v_{φ }}/σ _R, reaching v_c,JAM ≈ 2 × v_{c, ADC}. Such conditions indicate that the stellar masses of the galaxies in our sample are not confined to their disc planes and likely have a non-negligible contribution from their bulges and thick discs.