The stellar velocity dispersion in nearby spirals: radial profiles and correlations
Journal article, 2019

The stellar velocity dispersion, σ, is a quantity of crucial importance for spiral galaxies, where it enters fundamental dynamical processes such as gravitational instability and disc heating. Here we analyse a sample of 34 nearby spirals from the Calar Alto Legacy Integral Field Area (CALIFA) spectroscopic survey, deproject the line-of-sight σ to σR, and present reliable radial profiles of σR as well as accurate measurements of (σR), the radial average of σR over one effective (half-light) radius. We show that there is a trend for σR to increase with decreasing R, that (σR) correlates with stellar mass (M∗), and tested correlations with other galaxy properties. The most significant and strongest correlation is the one with M: (σR) ∞ M∗0.5. This tight scaling relation is applicable to spiral galaxies of type Sa-Sd and stellar mass M∗ ≈ 109.5 -1011.5 M. Simple models that relate σR to the stellar surface density and disc scale length roughly reproduce that scaling, but overestimate (σR) significantly.

galaxies: ISM-galaxies: kinematics and dynamics

ISM: kinematics and dynamics

instabilities

galaxies: structure

galaxies: star formation

Author

Keoikantse Moses Mogotsi

Southern African Large Telescope Foundation

South African Astronomical Observatory

Alessandro Romeo

Chalmers, Space, Earth and Environment, Astronomy and Plasmaphysics, Extragalactic Astrophysics

Monthly Notices of the Royal Astronomical Society

0035-8711 (ISSN) 1365-2966 (eISSN)

Vol. 489 3 3797-3809

Subject Categories

Astronomy, Astrophysics and Cosmology

Roots

Basic sciences

DOI

10.1093/mnras/stz2370

More information

Latest update

12/2/2019