The Relation between Stellar and Dynamical Surface Densities in the Central Regions of Disk Galaxies

Understand

We use the SPARC (Spitzer Photometry & Accurate Rotation Curves) database to study the relation between the central surface density of stars Sstar and dynamical mass Sdyn in 135 disk galaxies (S0 to dIrr).

• We find that Sdyn correlates tightly with Sstar over 4 dex.
• This central density relation can be described by a double power law.
• High surface brightness galaxies are consistent with a 1:1 relation, suggesting that they are self-gravitating and baryon dominated in the inner parts.