The stellar orbit distribution of 24 late-type galaxies observed by MUSE

Abstract

We selected 24 nearby late-type galaxies from the MUSE archive with kinematic coverage extending to at least one effective radius. Stellar kinematics were extracted with the GIST pipeline using pPXF, and axisymmetric Schwarzschild models were constructed with dynamite. The stellar orbits of each galaxy were classified by circularity into dynamically cold, warm, hot, and counter-rotating components, and we calculated the corresponding luminosity fractions of each component within Re. Our results confirm the mass-dependent trends in orbital structure previously identified from CALIFA galaxies and reproduced by IllustrisTNG. We further checked the morphology of each component and calculated the edge-on flattening of the cold, warm, and hot+CR components. With the high-quality MUSE data, we find that the dynamically warm components are common in low-mass late-type spiral galaxies, suggesting that their discs are dynamically warmer and vertically thicker than those of more massive spirals. We regard this as a tentative result, given the limited sample size.