2005/09/21 by Kambiz Fathi, Glenn van de Ven, R. F. Peletier +8 · 2 citations
Physics and Astronomy · #Astronomy and Astrophysical Research #Astrophysics #Barred spiral galaxy #Classical mechanics #Disc galaxy #Dust lane #Galaxies: Formation, Evolution, Phenomena #Galaxy #Galaxy formation and evolution #Kinematics #Milky Way #Physics #Spiral galaxy #Star formation #Stars #Stellar kinematics #Stellar, planetary, and galactic studies #astro-ph
paper · pdf · doi:10.1111/j.1365-2966.2005.09648.x
11 pages, 8 figures. Accepted for publication in MNRAS. Please find high resolution version on http://www.astro.uu.se/~kambiz/DOC/paper-N5448.pdf
arxiv created 2005/09/21 · openalex publication_date 2005/11/07 · arxiv updated 2015/06/24 · openalex created_date 2016/06/24 · openalex updated_date 2026/08/05
We analyse Spectrographic Areal Unit for Research on Optical Nebulae (SAURON) kinematic maps of the inner kiloparsec of the early-type (Sa) barred spiral galaxy NGC 5448. The observed morphology and kinematics of the emission-line gas is patchy and perturbed, indicating clear departures from circular motion. The kinematics of the stars is more regular, and display a small inner disc-like system embedded in a large-scale rotating structure. We focus on the [O iii] gas, and use a harmonic decomposition formalism to analyse the gas velocity field. The higher order harmonic terms and the main kinematic features of the observed data are consistent with an analytically constructed simple bar model. The bar model is derived using linear theory, considering an m= 2 perturbation mode, and with bar parameters that are consistent with the large-scale bar detected via imaging. We also study optical and near infrared images to reveal the asymmetric extinction in NGC 5448, and we recognize that some of the deviations between the data and the analytical bar model may be due to these complex dust features. Our study illustrates how the harmonic decomposition formalism can be used as a powerful tool to quantify non-circular motions in observed gas velocity fields.