2002/03/12 by L. D. Matthews, Lynn T. Matthews, J. S. Gallagher +1 · 38 citations
Physics and Astronomy · #Astronomy #Astronomy and Astrophysical Research #Astrophysics #Galaxies: Formation, Evolution, Phenomena #Galaxy #Galaxy formation and evolution #Galaxy rotation curve #Luminosity #Physics #Spiral galaxy #Stellar, planetary, and galactic studies #astro-ph
paper · pdf · doi:10.1086/340647
published in The Astrophysical Journal Supplement Series 141(2), 429-442 (Institute of Physics) · 20 pages; accepted to ApJS; higher resolution version of Figure 1 available as .png file
arxiv created 2002/03/12 · openalex publication_date 2002/08/01 · arxiv updated 2012/08/27 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/05
We present optical long-slit spectroscopic observations of 21 low-luminosity, extreme late-type spiral galaxies. Our sample is comprised of Sc-Sm Local Supercluster spirals with moderate-to-low optical surface brightnesses and with luminosities at the low end for spiral disk galaxies ( M V ≥ -18.8). For each galaxy we have measured high spatial resolution position-velocity (P-V) curves using the Hα emission line, and for 15 of the galaxies we also derive major-axis rotation curves. In ∼50% of our sample, the P-V curves show significant asymmetries in shape, extent, and/or amplitude on the approaching and receding sides of the disk. A number of the P-V curves are still rising to the last measured point or reach a clear turnover on only one side. In most instances we find good agreement between the kinematic centers of extreme late-type spirals as defined by the global H I emission profile and by their optical continuum, although in a few cases we see evidence of possible real offsets. In spite of their shallow central gravitational potentials, at least six of the galaxies in our sample possess semi-stellar nuclei that appear to be compact nuclear star clusters; in five of these cases we see kinematic signatures in the P-V curves at the location of the nucleus. Finally, we find that like giant spirals, our sample galaxies have higher specific angular momenta than predicted by current cold dark matter models.