Kinematic alignment of non-interacting CALIFA galaxies

Abstract

We present 80 stellar and ionised gas velocity maps from the Calar Alto Legacy Integral Field Area (CALIFA) survey in order to characterise the kinematic orientation of non-interacting galaxies. The study of galaxies in isolation is a key step towards understanding how fast-external processes, such as major mergers, affect kinematic properties in galaxies. We derived the global and individual (projected approaching and receding sides) kinematic position angles (PAs) for both the stellar and ionised gas line-of-sight velocity distributions. When compared to the photometric PA, we find that morpho-kinematic differences are smaller than 22 degrees in 90% of the sample for both stellar and nebular components and that internal kinematic misalignments are generally smaller than 16 degrees. We find a tight relation between the global stellar and ionised gas kinematic PA consistent with circular-flow pattern motions in both components (∼90% of the sample has differences smaller than 16 degrees). This relation also holds, generally in barred galaxies across the bar and galaxy disc scales. Our findings suggest that even in the presence of strong bars, both the stellar and the gaseous components tend to follow the gravitational potential of the disc. As a result, kinematic orientation can be used to assess the degree of external distortions in interacting galaxies.

The SLUGGS Survey: stellar kinematics, kinemetry and trends at large radii in 25 early-type galaxies

“…We find no measurable differences between our outer Ψouter values and the inner values (Ψ0) quoted in Krajnović et al (2011) within these large uncertainties. This is consistent with results presented in Barrera-Ballesteros et al (2014) for the CALIFA sample who found that the inner and outer kinematic position angles of gas and stars are usually well aligned.…”

“…The comparison of the central LOSVD in 2D to that expected from simple rotation or purely pressuresupported systems, and their correspondence (or otherwise) with photometrically identified substructures, have already greatly informed our understanding of the structures of galaxies (e.g. Krajnović et al 2008;Emsellem et al 2011;Barrera-Ballesteros et al 2014;Emsellem et al 2014). Indeed, while photometric studies reveal the projected 2D distribution of stars on the sky, the added dimension of spectroscopy affords the possibility of disentangling the true 3D shapes of galaxies (Weijmans et al 2014).…”

Ionized gas kinematics of galaxies in the CALIFA survey

“…These two approaches of the photometric position angles are also used in Falcón-Barroso et al (in prep. ) for the statistical analysis of the stellar kinematics of a sample of CALIFA galaxies and in Barrera-Ballesteros et al (2014) for the comparison of stellar and ionized gas kinematic for a sample of non-interacting galaxies. Figure 11 shows the comparison of these photometric position angles with the orientation of the velocity fields following Eq.…”

“…11f). Barrera-Ballesteros et al (2014) study the morpho-kinematic misaligments (as well as the stellarionized gas kinematic misaligments) for a sample of interacting galaxies.…”

CALIFA, the Calar Alto Legacy Integral Field Area survey

“…We explored the effects of the dilution of the signal in different gas and stellar population properties (Mast et al 2014), and proposed a new empirical aperture correction for the SDSS data (Iglesias-Páramo et al 2013); (v) we analyzed the local properties of the ionized gas and stellar population of galaxies where supernovae (SNe) have exploded. Core collapse SNe are found closer to younger stellar populations, while SNe Ia show no correlation to stellar age (Galbany et al 2014);(vi) CALIFA is the first IFS survey that allows gas and stellar kinematic studies for all morphologies with sufficient spectroscopic resolution to study (a) the kinematics of the ionized gas (García-Lorenzo et al 2015); (b) the effects of bars in the kinematics of galaxies (Barrera-Ballesteros et al 2014); (c) the effects of the interaction stage on the kinematic signatures (Barrera-Ballesteros et al, in prep. ); (d) the bar pattern speeds in late-type galaxies (Aguerri et al 2015); (e) the measurements of the angular momentum of galaxies to previously unexplored ranges of morphology and ellipticity (Falcón-Barroso et al, in prep.…”