SDSS-IV MaNGA : spatial resolved properties of kinematically misaligned galaxies

TL;DR

This study analyzes 456 kinematically misaligned galaxies from MaNGA, revealing that external gas accretion affects their kinematics, star formation, and metallicity, with differences observed across galaxy types.

Contribution

It provides a detailed comparison of spatially resolved properties of misaligned galaxies with control samples, highlighting the impact of external gas accretion on galaxy evolution.

Findings

Misaligned galaxies have lower ordered-to-random motion ratios.

Star-forming and green-valley misaligned galaxies show enhanced central star formation.

Green valley and quiescent misaligned galaxies have lower gas-phase metallicity.

Abstract

We select 456 galaxies with kinematically misaligned gas and stellar components from 9546 parent galaxies in MaNGA, and classify them into 72 star-forming galaxies, 142 green-valley galaxies and 242 quiescent galaxies. Comparing the spatial resolved properties of the misaligned galaxies with control samples closely match in the D$_n$4000 and stellar velocity dispersion, we find that: (1) the misaligned galaxies have lower values in $V_{\rm gas}/{\sigma}_{\rm gas}$ and $V_{\rm star}/{\sigma}_{\rm star}$ (the ratio between ordered to random motion of gas and stellar components) across the entire galaxies than their control samples; (2) the star-forming and green-valley misaligned galaxies have enhanced central concentrated star formation than their control galaxies. The difference in stellar population between quiescent misaligned galaxies and control samples is small; (3) gas-phase metallicity of the green valley and quiescent misaligned galaxies are lower than the control samples. For the star forming misaligned galaxies, the difference in metallicity between the misaligned galaxies and their control samples strongly depends on how we select the control samples. All these observational results suggest external gas accretion influences the evolution of star forming and green valley galaxies, not only in kinematics/morphologies, but also in stellar populations. However, the quiescent misaligned galaxies have survived from different formation mechanisms.