Volume 468, Number 2, June III 2007The XMM-Newton extended survey of the Taurus molecular cloud
|Page(s)||731 - 774|
|Published online||03 April 2007|
Kinematic modelling of disk galaxies
I. A new method to fit tilted rings to data cubes
Argelander Institute for Astronomy (AIfA), Univ. Bonn, Auf dem Hügel 71, 53121 Bonn, Germany e-mail: [gjozsa;fkenn;uklein]@astro.uni-bonn.de
2 Netherlands Foundation for Research in Astronomy, Postbus 2, 7990 AA Dwingeloo, The Netherlands e-mail: email@example.com
3 Kapteyn Astronomical Institute, Univ. Groningen, Postbus 800, 9700 AV Groningen, The Netherlands
Accepted: 2 March 2007
This is the first of a series of papers in which the kinematics of disk galaxies over a range of scales is scrutinised by employing spectroscopy. A fundamental aspect of these studies is presented here: the new publicly available software tool TiRiFiC (http://www.astro.uni-bonn.de/∼gjozsa/tirific.html) enables a direct fit of a “tilted-ring model” to spectroscopic data cubes. The algorithm generates model data cubes from the tilted-ring parametrisation of a rotating disk, which are automatically adjusted to reach an optimum fit via a chi-squared minimisation method to an observed data cube. The structure of the new software, the shortcomings of the previously available programs to produce a tilted-ring model, and the performance of TiRiFiC are discussed. Our method is less affected by the well-known problem of beam smearing that occurs when fitting to the velocity field. Since we fit many data points in a data cube simultaneously with our method, TiRiFiC is sensitive to very faint structures so can be used to derive tilted-ring models significantly extending in radius beyond those derived from a velocity field. The software is able to parametrise H I disks of galaxies that are intersected by the line-of-sight twice or more, i.e. if the disks are heavily warped, and/or with a significant shift of the projected centre of rotation, and/or if seen edge-on. Furthermore, our method delivers the surface-brightness profile of the examined galaxy in addition to the orientational parameters and the rotation curve. In order to derive kinematic and morphological models of disk galaxies, especially reliable rotation curves, a direct-fit method as implemented in our code should be the tool of choice.
Key words: methods: data analysis / galaxies: kinematics and dynamics / galaxies: structure
© ESO, 2007
Current usage metrics show cumulative count of Article Views (full-text article views including HTML views, PDF and ePub downloads, according to the available data) and Abstracts Views on Vision4Press platform.
Data correspond to usage on the plateform after 2015. The current usage metrics is available 48-96 hours after online publication and is updated daily on week days.
Initial download of the metrics may take a while.