Star formation in CALIFA survey perturbed galaxies – III. Stellar and ionized-gas kinematic distributions

Abstract

ABSTRACT We obtain the kinematic distributions of stars (synthetic model line absorption) and ionized gas (H α line emission) for star-forming regions residing in Calar Alto Legacy Integral Field Area survey tidally perturbed (perturbed) and non-tidally perturbed (control) galaxies. We set the uncertainties of the velocity dispersion by measuring the statistical variability of the data sets themselves. Using these adopted uncertainties and considering the sensitivity of the grating device, we establish thresholds of reliability that allow us to select reliable velocity dispersions. From this selection, we pair the star-forming spaxels between control and perturbed galaxies at the closest shifts in velocity (de-redshifting). We compare their respective distributions of velocity dispersion. In perturbed galaxies, median velocity dispersions for the stellar and gaseous components are minimally higher and equal, respectively, than those in control galaxies. The spread in velocity dispersion and the velocity shift–velocity dispersion space agree with this result. Unlike the well-known trend in strongly interacting systems, the stellar and ionized-gas motions are not disturbed by the influence of close companions. For the gaseous component, this result is due to the poor statistical variability of its data, a consequence of the tightness in velocity dispersion derived from high spectral line intensities. This analysis concludes the series, which previously showed star-forming regions in galaxies with close companions undergoing more prominent gas inflows, resulting in differences in their star formation and consequent metal content.