2004/03/10 by Aeree Chung, A. Chung, M. Bureau · 5 citations
Physics and Astronomy · #Astronomy and Astrophysical Research #Astrophysics and Star Formation Studies #Asymmetry #Bar (unit) #Bulge #Galaxies: Formation, Evolution, Phenomena #Galaxy #Galaxy rotation curve #Kinematics #Rotational symmetry #Spiral galaxy #Stellar kinematics #Velocity dispersion #astro-ph
paper · pdf · doi:10.1086/420988
45 pages, 9 figures, 2 tables, AASTeX preprint. Accepted for publication in The Astronomical Journal. We strongly suggest you download the version with full resolution figures at http://www.astro.columbia.edu/~bureau/Publications/Peanuts_starkin_AJ04.ps.gz
arxiv created 2004/03/10 · openalex publication_date 2004/06/01 · openalex created_date 2016/06/24 · openalex updated_date 2026/08/05
Major-axis long-slit stellar kinematics was obtained for 30 edge-on spiral galaxies, 24 with a boxy/peanut-shaped (B/PS) bulge. B/PS bulges are present in >45% of highly inclined systems and much work suggests that they are the edge-on projection of thick bars. Profiles of the mean stellar velocity V, the velocity dispersion sigma, and the asymmetric (h3) and symmetric (h4) deviations from a Gaussian are presented. Comparing those with N-body bar diagnostics, we find bar signatures in 80% of our sample. B/PS bulge galaxies typically show a double-hump rotation curve with an intermediate dip or plateau. They often show a flat central velocity dispersion profile accompanied by a secondary peak or plateau and >=40% have a local central sigma minimum. The h3 profiles display up to 3 slope reversals and h3 is normally correlated with V over the presumed bar length, contrary to expectations from axisymmetric disks. Those characteristic bar signatures strengthen the case for a close link between B/PS bulges and bars. h3 is anti-correlated with V in the very center of most galaxies, indicating that they additionally harbor cold and dense decoupled nearly axisymmetric central stellar disks. These coincide with previously identified star-forming ionized-gas disks in the gas-rich systems, and we argue that they formed out of gas inflow driven by the bar. As suggested by N-body models, h3 appears to be a reliable tracer of asymmetries in disks, allowing to discriminate between axisymmetric and barred disks seen in projection. B/PS bulges (and thus a large fraction of all bulges) appear to be made-up mostly of disk material which has acquired a large vertical extent through bar-driven vertical instabilities. Their formation is thus probably dominated by secular evolution processes rather than merging. [Abridged]