Gas dynamics in dwarf galaxies

In the recent paper “Gas dynamics in dwarf galaxies as testbeds for dark matter and galaxy evolution” (Nature Astronomy, 2022), Federico Lelli reviews several key aspects of gas dynamics in low-mass (dwarf) galaxies, such as their rotation curves, mass models and non-circular motions.
Dwarf galaxies are ideal laboratories to test dark matter models and alternative gravitational theories because their dynamical mass (from observed kinematics) largely outweighs their baryonic mass (from gas and stars). In most star-forming dwarf galaxies, cold atomic gas forms regularly rotating disks extending beyond the stellar component, so it offers a key tool to trace the gravitational potential out to the outermost galaxy regions.
Star-forming dwarfs extend the dynamical laws of spiral galaxies to lower masses, surface densities and accelerations. The three main dynamical laws of rotation-supported galaxies (spirals and dwarf irregulars) point to three distinct acceleration scales, which play different physical roles but display the same numerical value, within uncertainties. The small scatter around these dynamical laws implies a tight coupling between baryons and dark matter in galaxies, which will be better understood with next-generation surveys with SKA pathfinders, that will enlarge current sample sizes by orders of magnitude.


The star-forming dwarf galaxy DDo 125.Credits: Lelli et al. 2022


First author: Federico Lelli, This email address is being protected from spambots. You need JavaScript enabled to view it.