Scaling Laws for Dark Matter Halos in Late-Type and Dwarf Spheroidal Galaxies

Understand

Dark matter (DM) halos of Sc-Im and dwarf spheroidal (dSph) galaxies satisfy scaling laws: halos in lower-luminosity galaxies have smaller core radii, higher central densities, and smaller velocity dispersions.

• These results are based on maximum-disk rotation curve decompositions for giant galaxies and Jeans equation analysis for dwarfs.
• (1) We show that spiral, Im, and Sph galaxies with absolute magnitudes M_V > -18 form a sequence of decreasing baryon-to-DM surface density with decreasing luminosity.
• We suggest that this is a sequence of decreasing baryon retention vs.