1999/01/21 by John Magorrian · 6 citations
Physics and Astronomy · #Astrophysical Phenomena and Observations #Galaxies: Formation, Evolution, Phenomena #Stellar, planetary, and galactic studies #astro-ph
paper · pdf · doi:10.1046/j.1365-8711.1999.02135.x
published as Mon.Not.Roy.Astron.Soc. 302 (1999) 530 · 7 pages, 7 figures, uses mn.tex
openalex publication_date 1999/01/21 · arxiv created 1999/02/02 · arxiv updated 2009/12/01 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/30
The deprojection of the surface brightness distribution of an axisymmetric galaxy does not have a unique solution unless the galaxy is viewed precisely edge-on. I present an algorithm that finds the full range of smooth axisymmetric density distributions consistent with a given surface brightness distribution and inclination angle, and use it to investigate the effects of this non-uniqueness on the line-of-sight velocity profiles (VPs) of two-integral models of both real and toy discy galaxies viewed at a range of inclination angles. Photometrically invisible face-on discs leave very clear signatures in the minor-axis VPs of the models (Gauss-Hermite coefficients h4= 0.1), provided the disc-to-bulge ratio is greater than about 3 per cent. I discuss the implications of these hitherto neglected discs for dynamical modelling.