Issue |
A&A
Volume 576, April 2015
|
|
---|---|---|
Article Number | A57 | |
Number of page(s) | 8 | |
Section | Extragalactic astronomy | |
DOI | https://doi.org/10.1051/0004-6361/201425279 | |
Published online | 27 March 2015 |
Disk mass and disk heating in the spiral galaxy NGC 3223⋆
1
Sterrenkundig Observatorium, Universiteit Gent,
Krijgslaan 281,
9000
Gent,
Belgium
e-mail:
gianfranco.gentile@ugent.be
2
Department of Physics and Astrophysics, Vrije Universiteit
Brussel, Pleinlaan
2, 1050
Brussels,
Belgium
3
Department of Solid State Sciences, Krijgslaan 281, 9000
Gent,
Belgium
4
Netherlands Institute for Radio Astronomy (ASTRON),
Postbus 2, 7990 AA
Dwingeloo, The
Netherlands
5
Astrophysics, Cosmology and Gravity Centre, Department of
Astronomy, University of Cape Town, Private Bag X3, 7701
Rondebosch, South
Africa
6
Kapteyn Astronomical Institute, University of
Groningen, PO Box
800, 9700 AV
Groningen, The
Netherlands
Received: 5 November 2014
Accepted: 11 February 2015
We present the stellar and gaseous kinematics of an Sb galaxy, NGC 3223, with the aim of determining the vertical and radial stellar velocity dispersion as a function of radius, which can help to constrain disk heating theories. Together with the observed NIR photometry, the vertical velocity dispersion is also used to determine the stellar mass-to-light (M/L) ratio, typically one of the largest uncertainties when deriving the dark matter distribution from the observed rotation curve. We find a vertical-to-radial velocity dispersion ratio of σz/σR = 1.21 ± 0.14, significantly higher than expectations from known correlations, and a weakly-constrained Ks-band stellar M/L ratio in the range 0.5–1.7, which is at the high end of (but consistent with) the predictions of stellar population synthesis models. Such a weak constraint on the stellar M/L ratio, however, does not allow us to securely determine the dark matter density distribution. To achieve this, either a statistical approach or additional data (e.g. integral-field unit) are needed.
Key words: galaxies: kinematics and dynamics / galaxies: individual: NGC 3223 / galaxies: structure
© ESO, 2015
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