Turbulence-induced deviation between baryonic field and dark matter field in the spatial distribution of the Universe

Abstract

The cosmic baryonic fluid at low redshifts is similar to a fully developed turbulence. In this work, we use simulation samples produced by the hybrid cosmological hydrodynamical/N-body code, to investigate on what scale the deviation of spatial distributions between baryons and dark matter is caused by turbulence. For this purpose, we do not include the physical processes such as star formation, supernovae (SNe) and active galactic nucleus (AGN) feedback into our code, so that the effect of turbulence heating for IGM can be exhibited to the most extent. By computing cross-correlation functions $r_m(k)$ for the density field and $r_v(k)$ for the velocity field of both baryons and dark matter, we find that deviations between the two matter components for both density field and velocity field, as expected, are scale-dependent. That is, the deviations are the most significant at small scales and gradually diminish on larger and larger scales. Also, the deviations are time-dependent, i.e. they become larger and larger with increasing cosmic time. The most emphasized result is that the spatial deviations between baryons and dark matter revealed by velocity field are more significant than that by density field. At z = 0, at the 1% level of deviation, the deviation scale is about 3.7 $h^{-1}$Mpc for density field, while as large as 23 $h^{-1}$Mpc for velocity field, a scale that falls within the weakly non-linear regime for the structure formation paradigm. Our results indicate that the effect of turbulence heating is indeed comparable to that of these processes such as SN and AGN feedback.

13 pages, 9 figures

References in corpus (18)

• Five-Year Wilkinson Microwave Anisotropy Probe (WMAP) Observations: Cosmological Interpretation
• A direct empirical proof of the existence of dark matter
• Introducing the Illustris Project: Simulating the coevolution of dark and visible matter in the Universe
• Turbulent Heating in Galaxy Clusters Brightest in X-rays
• The Search for the Missing Baryons at Low Redshift
• A second galaxy missing dark matter in the NGC1052 group
• Shock Waves in Eulerian Cosmological Simulations: Main Properties and Acceleration of Cosmic Rays
• Modelling baryonic feedback for survey cosmology
• The Cosmic Code Comparison Project
• Analytic Prediction of Baryonic Effects from the EFT of Large Scale Structures
• Detection of the pairwise kinematic Sunyaev-Zel'dovich effect with BOSS DR11 and the Atacama Cosmology Telescope
• Vorticity of IGM Velocity Field on Large Scales
• Sampling Artifact in Volume Weighted Velocity Measurement.--- I. Theoretical Modelling
• Wide-Field InfraRed Survey Telescope (WFIRST) Interim Report
• Accurate initial conditions in mixed Dark Matter--Baryon simulations
• Low-Redshift Cosmic Baryon Fluid on Large Scales and She-Leveque Universal Scaling
• Constraining the optical depth of galaxies and velocity bias with cross-correlation between kinetic Sunyaev-Zeldovich effect and peculiar velocity field
• Statistical and dynamical decoupling of the IGM from Dark Matter