Disk mass and disk heating in the spiral galaxy NGC 3223

Gentile, G; Tydtgat, C; Baes, M; De Geyter, G; Koleva, M; Angus, G W; de Blok, W J G; Saftly, W; Viaene, S

Disk mass and disk heating in the spiral galaxy NGC 3223

Journal Article

2015

Journal Title

Astronomy and Astrophysics

Link to Journal

https://dx.doi.org/10.1051/0004-6361/201425279

Department

Department of Astronomy

Faculty

Faculty of Science

Abstract

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 sigma(z)/sigma(R) = 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.