2008/11/30 by Remco C. E. van den Bosch, Glenn van de Ven · 4 citations
Physics and Astronomy · #Astronomy and Astrophysical Research #Disc galaxy #Elliptical galaxy #Flattening #Galaxies: Formation, Evolution, Phenomena #Galaxy #Kinematics #Peculiar galaxy #Photometry (optics) #Rotational symmetry #Stellar, planetary, and galactic studies #astro-ph
paper · pdf · doi:10.1111/j.1365-2966.2009.15177.x
12 pages, 7 figures, PDFLaTeX, accepted to MNRAS, minor revisions
arxiv created 2009/07/09 · openalex publication_date 2009/08/24 · arxiv updated 2009/12/01 · openalex created_date 2016/06/24 · openalex updated_date 2026/08/05
We investigate how well the intrinsic shape of early-type galaxies can be recovered when both photometric and two-dimensional stellar kinematic observations are available. We simulate these observations with galaxy models that are representative of observed oblate fast-rotator to triaxial slow-rotator early-type galaxies. By fitting realistic triaxial dynamical models to these simulated observations, we recover the intrinsic shape (and mass-to-light ratio), without making additional (ad-hoc) assumptions on the orientation. For (near) axisymmetric galaxies the dynamical modelling can strongly exclude triaxiality, but the regular kinematics do not further tighten the constraint on the intrinsic flattening significantly, so that the inclination is nearly unconstrained above the photometric lower limit even with two-dimensional stellar kinematics. Triaxial galaxies can have additional complexity in both the observed photometry and kinematics, such as twists and (central) kinematically decoupled components, which allows the intrinsic shape to be accurately recovered. For galaxies that are very round or show no significant rotation, recovery of the shape is degenerate, unless additional constraints such as from a thin disk are available.