Rotation curve analysis of dwarf galaxies from LVHIS

We present the rotation curves of seven dwarf galaxies from the Local Volume Hi Survey (LVHIS) to investigate their Hi gas kinematics and mass distribution. The LVHIS Hi data cubes, with a spatial resolution of 40–50″ and a spectral resolution of ∼4kms−1, allow for a detailed analysis of gas kinematics and the relative contributions of baryons and dark matter. Using a Bayesian–based profile decomposition method, we identify kinematic complexities in the gas, particularly in the inner regions, which may arise from observational beam smearing or stellar feedback processes. Through 2D tilted–ring analysis, we derive rotation curves that exhibit solid-body rotation in the inner regions, transitioning to flat or gradually rising curves in the outer parts. An asymmetric drift correction applied to the rotation curves shows minimal impact, attributed to the low Hi velocity dispersion and gas surface densities in the galaxies’ outer regions. Disk—halo decomposition using the Cold Dark Matter NFW and pseudo-isothermal halo models is limited by the coarse spatial resolution of the LVHIS Hi data and the absence of high–quality optical and infrared observations, which hinders a clear distinction between the models. Nonetheless, this study complements our understanding of the overall rotation curve shapes and Hi gas kinematics of galaxies in the local Universe.