Dark matter cores in massive high-$z$ galaxies formed by baryonic clumps

Abstract

The rotation curves of some star forming massive galaxies at redshift two decline over the radial range of a few times the effective radius, indicating a significant deficit of dark matter (DM) mass in the galaxy centre. The DM mass deficit is interpreted as the existence of a DM density core rather than the cuspy structure predicted by the standard cosmological model. A recent study proposed that a galaxy merger, in which the smaller satellite galaxy is significantly compacted by dissipative contraction of the galactic gas, can heat the centre of the host galaxy and help make a large DM core. By using an $N$-body simulation, we find that a large amount of DM mass is imported to the centre by the merging satellite, making this scenario an unlikely solution for the DM mass deficit. In this work, we consider giant baryonic clumps in high redshift galaxies as alternative heating source for creating the baryon dominated galaxies with a DM core. Due to dynamical friction, the orbit of clumps decays in a few Gyr and the baryons condensate at the galactic centre. As a back-reaction, the halo centre is heated up and the density cusp is flattened out. The combination of the baryon condensation and core formation makes the galaxy baryon dominated in the central 2-5 kpc, comparable to the effective radius of the observed galaxies. Thus, the dynamical heating by giant baryonic clumps is a viable mechanism for explaining the observed dearth of DM in high redshift galaxies.

11 pages, 7 figures, 1 table and 1 appendix, accepted for publication in MNRAS

References in corpus (34)

• Cold streams in early massive hot haloes as the main mode of galaxy formation
• 3D-HST+CANDELS: The Evolution of the Galaxy Size-Mass Distribution since $z=3$
• Formation of Massive Galaxies at High Redshift: Cold Streams, Clumpy Disks and Compact Spheroids
• Concentration, Spin and Shape of Dark Matter Haloes as a Function of the Cosmological Model: WMAP1, WMAP3 and WMAP5 results
• Compaction and Quenching of High-z Galaxies in Cosmological Simulations: Blue and Red Nuggets
• The rapid formation a large rotating disk galaxy three billion years after the Big Bang
• Rapid formation of exponential disks and bulges at high redshift from the dynamical evolution of clump cluster and chain galaxies
• High-resolution mass models of dwarf galaxies from LITTLE THINGS
• A universal model for halo concentrations
• Disruption of Dark Matter Substructure: Fact or Fiction?
• Strongly baryon-dominated disk galaxies at the peak of galaxy formation ten billion years ago
• Dark Matter Substructure in Numerical Simulations: A Tale of Discreteness Noise, Runaway Instabilities, and Artificial Disruption
• The Current Status of Galaxy Formation
• A fitting formula for the merger timescale of galaxies in hierarchical clustering
• Resolved spectroscopy of gravitationally lensed galaxies: global dynamics and star-forming clumps on ~100pc scales
• Angular momentum properties of haloes and their baryon content in the Illustris simulation
• Early flattening of dark matter cusps in dwarf spheroidal galaxies
• Larson's scaling laws, and the gravitational instability of clumpy discs at high redshift
• Rings and Bent Chain Galaxies in the GEMS and GOOD Fields
• DASH: a library of dynamical subhalo evolution
• Radialization of satellite orbits in galaxy mergers
• Structure Formation in Gas-Rich Galactic Discs with Finite Thickness: From Discs to Rings
• The Influence of Mass-Loss from a Star Cluster on its Dynamical Friction -- I. Clusters without Internal Evolution
• The kinematics of massive quiescent galaxies at $1.4<z<2.1$: dark matter fractions, IMF variation, and the relation to local early-type galaxies
• From giant clumps to clouds I: the impact of gas fraction evolution on the stability of galactic discs
• The MUSE Extremely Deep Field: Evidence for SFR-induced cores in dark-matter dominated galaxies at z=1
• Clumpy high-z galaxies as a testbed for feedback-regulated galaxy formation
• From giant clumps to clouds -- II. The emergence of thick disc kinematics from the conditions of star formation in high redshift gas rich galaxies
• Clump Survival and Migration in VDI Galaxies: an Analytic Model versus Simulations and Observations
• Properties of thick discs formed in clumpy galaxies
• Core Formation in High-z Massive Haloes: Heating by Post Compaction Satellites and Response to AGN Outflows
• Dark Matter Fraction in z~1 Star-Forming Galaxies
• The possible hierarchical scales of observed clumps in high-redshift disc galaxies
• The central dark matter fraction of massive early-type galaxies

Cited by in corpus (6)

• RC100: Rotation Curves of 100 Massive Star-Forming Galaxies at z=0.6-2.5 Reveal Little Dark Matter on Galactic Scales
• A ~600 pc view of the strongly-lensed, massive main sequence galaxy J0901: a baryon-dominated, thick turbulent rotating disk with a clumpy cold gas ring at z = 2.259
• The Response of Dark Matter Haloes to Gas Ejection: CuspCore II
• On the origin of compressive turbulence in protoclumps in high redshift disks
• Halo heating from fluctuating gas in a model dwarf
• Two-phase formation of galaxies: the coevolution between galaxies and dark matter halos