Disk mass and disk heating in the spiral galaxy NGC 3223

作者：Gentile G^*; Tydtgat C; Baes M; De Geyter G; Koleva M; Angus G W; de Blok W J G; Saftly W; Viaene S

来源：Astronomy & Astrophysics, 2015, 576: A57.

DOI：10.1051/0004-6361/201425279

• galaxies: kinematics and dynamics
• galaxies: individual: NGC 3223
• galaxies: structure

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.

• 出版日期2015-4