Exploring stellar and ionized gas non--circular motions in barred galaxies with MUSE

TL;DR

This study uses MUSE integral field data to analyze non-circular stellar and gas motions in 14 barred galaxies, revealing bar-induced streaming motions and modeling these kinematics with bisymmetric and harmonic approaches.

Contribution

It demonstrates the effectiveness of MUSE in detecting kinematic signatures of bars and compares different models to characterize non-circular motions in barred galaxies.

Findings

Bars induce streaming motions detectable in velocity maps.

Both bisymmetric and harmonic models successfully reproduce observed kinematics.

No correlation found between non-circular motion amplitude and bar size, stellar mass, or SFR.

Abstract

We present MUSE integral field stellar and ionized velocity maps for a sample of 14 barred galaxies. Most of these objects exhibit "S"-shape iso-velocities in the bar region indicative of the presence of streaming motions in the velocity fields. % By applying circular rotation models we observe that bars leave symmetric structures in the residual maps of the stellar velocity. %which demonstrates the capabilities of the MUSE instrument for detecting kinematic bar signatures. % We built non-circular rotation models using the \xs~tool to characterize the observed velocity fields. In particular we adopt bisymmetric models and a harmonic decomposition for a bar potential for describing the non-axisymmetric velocities. We find that both models reproduce the observed kinematic features. % The position angle of the oval distortion estimated from the bisymmetric model correlates with the photometric bar position angle $(\rho_{pearson} = 0.95)$, which suggest that non-circular velocities are caused by the bar. However because of the low amplitudes of the $s_3$ harmonic we can not rule out radial flows as possible source. % Because of the weak detection of \ha~in our objects we are not able to compare gas to stellar non-circular motions in our sample, although we show that when galaxies are gas rich the oval distortion is also observed but with larger amplitudes. % Finally, we do not find evidence that the amplitude of the non-circular motions is dependent on the bar size, stellar mass or the global SFR.