Collisional baryonic dark matter halos

Abstract

If dark halos are composed of dense gas clouds, as has recently been inferred, then collisions between clouds lead to galaxy evolution. Collisions introduce a core in an initially singular dark matter distribution, and can thus help to reconcile scale-free initial conditions -- such as are found in simulations -- with observed halos, which have cores. A pseudo-Tully-Fisher relation, between halo circular speed and visible mass (not luminosity), emerges naturally from the model: visible mass proportional to V^3.5. Published data conform astonishingly well to this theoretical prediction. For our sample of galaxies, the mass-velocity relationship has much less scatter than the Tully-Fisher relation, and holds as well for dwarf galaxies (where diffuse gas makes a sizeable contribution to the total visible mass) as it does for giants. It seems very likely that this visible-mass/velocity relationship is the underlying physical basis for the Tully-Fisher relation, and this discovery in turn suggests that the dark matter is both baryonic and collisional.

Revised version; 6 pages, 2 figures, to appear in MNRAS

References in corpus (5)

• The Cores of Dark Matter Dominated Galaxies: theory vs. observations
• Testing the Dark Matter Hypothesis with Low Surface Brightness Galaxies and Other Evidence
• Optical Rotation Curves of Distant Field Galaxies: Sub-L* Systems
• Extreme scattering events and Galactic dark matter
• Lensing of Stars by Spherical Gas Clouds

Cited by in corpus (24)

• The Baryonic Tully-Fisher Relation
• The Baryonic Tully-Fisher Relationship for S${}^4$G Galaxies and the "Condensed" Baryon Fraction of Galaxies
• The HI Tully-Fisher Relation of Early-Type Galaxies
• Dynamical friction of bodies orbiting in a gaseous sphere
• A Slippery Slope: Systematic Uncertainties in the Line Width Baryonic Tully-Fisher Relation
• Thermal stability of cold clouds in galaxy halos
• A Consistent Set of Empirical Scaling Relations for Spiral Galaxies: The $(v_{\max },M_{\mathrm{DM}})$-$({\sigma }_0,M_{\mathrm{BH}},\varphi )$ Relations
• Structural Parameters of Stellar Disks from 2MASS Images of Edge-on Galaxies
• Relations between abundance characteristics and rotation velocity for star-forming MaNGA galaxies
• The Intrinsic Scatter of the Radial Acceleration Relation
• ZOMG III: The effect of Halo Assembly on the Satellite Population
• The scaling relation between baryonic mass and stellar disc size of morphologically late-type galaxies
• Giant disk galaxies : Where environment trumps mass in galaxy evolution
• Constraints on Cold H_2 Clouds from Gravitational Microlensing Searches
• A snowflake's chance in heaven
• The Cloudy Universe
• Dense gas clouds and the Unidentified EGRET sources
• Cosmic snow clouds: self-gravitating gas spheres manifesting hydrogen condensation
• Gamma-ray Spectra due to Cosmic-ray Interactions with Dense Gas Clouds
• Free-floating "planets'' in the macrolensed quasar Q2237+0305
• Cosmological nanolensing by dense gas clouds
• Tidal disruption of "snow clouds" by unassociated stars
• Search for H2 cloudlets in our backyard
• The Tully-Fisher relations of the Eridanus group of galaxies