Ha kinematics of S^sup 4^G spiral galaxies - III. Inner rotation curves

• Published in: Monthly notices of the Royal Astronomical Society 2016-05, Vol.458 (2), p.1199
• Main Authors: Erroz-Ferrer, Santiago, Knapen, Johan H, Leaman, Ryan, Díaz-García, Simón, Salo, Heikki, Laurikainen, Eija, Querejeta, Miguel, Muñoz-Mateos, Juan Carlos, Athanassoula, E, Bosma, Albert, Comerón, Sebastien, Elmegreen, Bruce G, Martínez-Valpuesta, Inma
• Format: Article
• Language: English
• Subjects: Correlation analysis; Cosmology; Fourier analysis; Kinematics; Luminosity; Orbits; Star & galaxy formation
• ISSN: 0035-8711; 1365-2966

We present a detailed study of the shape of the innermost part of the rotation curves of a sample of 29 nearby spiral galaxies, based on high angular and spectral resolution kinematic Hα Fabry-Perot observations. In particular, we quantify the steepness of the rotation curve by measuring its slope d^sub R^v^sub c^(0). We explore the relationship between the inner slope and several galaxy parameters, such as stellar mass, maximum rotational velocity, central surface brightness (...), bar strength and bulge-to-total ratio. Even with our limited dynamical range, we find a trend for low-mass galaxies to exhibit shallower rotation curve inner slopes than high-mass galaxies, whereas steep inner slopes are found exclusively in high-mass galaxies. This trend may arise from the relationship between the total stellar mass and the mass of the bulge, which are correlated among them. We find a correlation between the inner slope of the rotation curve and the morphological T-type, complementary to the scaling relation between d^sub R^v^sub c^(0) and ... previously reported in the literature. Although we find that the inner slope increases with the Fourier amplitude A^sub 2^ and decreases with the bar torque Q^sub b^, this may arise from the presence of the bulge implicit in both A^sub 2^ and Q^sub b^. As previously noted in the literature, the more compact the mass in the central parts of a galaxy (more concretely, the presence of a bulge), the steeper the inner slopes. We conclude that the baryonic matter dominates the dynamics in the central parts of our sample galaxies. (ProQuest: ... denotes formulae/symbols omitted.)