2025/09/15 by Q. Zhang, Min Bao, Zhang, Qianhan +9
Engineering · Physics and Astronomy · #Astronomical Observations and Instrumentation #Astronomy and Astrophysical Research #Astrophysics and Star Formation Studies #Astrophysics of Galaxies (astro-ph.GA) #FOS: Physical sciences
paper · pdf · doi:10.48550/arxiv.2509.11891
openalex publication_date 2025/09/15 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/05
Using the data from Mapping Nearby Galaxies at Apache Point Observatory (MaNGA) and HI-MaNGA surveys, we build a sample of 37 gas-star misaligned galaxies with robust HI detections, which are believed to have undergone external gas accretion processes. Both star-forming (SF) and quiescent (QS) misaligned galaxies exhibit narrower HI linewidths compared to their gas-star aligned controls. The HI profiles of SF misaligned galaxies tend to be single-peaked, displaying a slightly higher fraction of single-peaked shape compared to their aligned controls. The QS misaligned galaxies exhibit prominently single-peaked HI profiles, while their aligned controls show distinct double-horned profiles. The shape of HI profiles is expected to change with the HI surface density radial gradients through external gas accretion -- the interaction between the accreted gas and the pre-existing gas leads to the re-distribution of angular momentum and induces gas inflow. It suggests that the progenitors of SF misaligned galaxies are central HI-enriched, in this case, the shape of HI profiles is insensitive to the further increase of central HI surface density. The progenitors of QS misaligned galaxies are central HI-deficient, hence the transition from central HI-deficient to HI-enriched surface density leads to significantly more single-peaked HI profiles.