The formation of the first cosmic structures and the physics of the z~20 Universe

Abstract

We perform a suite of cosmological simulations in the LCDM paradigm of the formation of the first structures in the Universe prior to astrophysical reheating and reionization (15<~z<200). These are the first simulations initialized in a manner that self consistently account for the impact of pressure on the rate of growth of modes, temperature fluctuations in the gas, and the dark matter-baryon supersonic velocity difference. Even with these improvements, these are still difficult times to simulate accurately as the Jeans length of the cold intergalactic gas must be resolved while also capturing a representative sample of the Universe. Our simulations support the finding of recent studies that the dark matter-baryon velocity difference has a surprisingly large impact on the accretion of gas onto the first star-forming minihalos (with masses of ~10^6 Msun). In fact, the halo gas is often significantly downwind of such halos and with lower densities, which delays the formation of the first stars in most locations in the Universe. We also show that dynamical friction plays an important role in the nonlinear evolution of the differential velocity, acting to erase this velocity difference quickly in overdense gas as well as sourcing visually-apparent bow shocks and Mach cones throughout the Universe. We use simulations with both the GADGET and Enzo cosmological codes to test the robustness of these conclusions. We find that particle coupling in GADGET between the gas and dark matter particles can result in spurious growth that mimics nonlinear growth in the matter power spectrum. In a companion paper, we use the simulations presented here to make detailed estimates for the impact of the dark matter--baryon velocity differential on redshifted 21cm radiation. The initial conditions generator used in this study CICsASS can be publicly downloaded.

ApJ in press. Abstract Abridged. 21 Pages. 17 Figures. Minor changes, except we show that adaptive gravitational softening in SPH simulations is required to alleviate particle coupling. Movies and pictures are available at http://astro.berkeley.edu/~mmcquinn/firstlight Initial conditions code can be obtained at http://astro.berkeley.edu/~mmcquinn/Init_Cond_Code.html

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• Probing the First Stars and Black Holes in the Early Universe with the Dark Ages Radio Explorer (DARE)
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• Power spectrum extraction for redshifted 21-cm epoch of reionization experiments: the LOFAR case
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• Third-order Perturbation Theory With Non-linear Pressure
• Introducing Enzo, an AMR Cosmology Application

Cited by in corpus (70)

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• Higher-order initial conditions for mixed baryon-CDM simulations
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• Heating the IGM by X-rays from Population III Binaries in High Redshift Galaxies
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• How closely do baryons follow dark matter on large scales?
• Globular Clusters and Dark Satellite Galaxies through the Stream Velocity
• Supersonic Relative Velocity between Dark Matter and Baryons: A Review
• Formation of the first star clusters and massive star binaries by fragmentation of filamentary primordial gas clouds
• The 21-cm BAO signature of enriched low-mass galaxies during cosmic reionization
• Impact of baryonic streaming velocities on the formation of supermassive black holes via direct collapse
• Axion Star Explosions: A New Source for Axion Indirect Detection
• Low-mass suppression of the satellite luminosity function due to the supersonic baryon--cold-dark-matter relative velocity
• The Supersonic Project: Shining Light on SIGOs - a New Formation Channel for Globular Clusters
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• Baryon-CDM isocurvature galaxy bias with IllustrisTNG
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• Small-scale structure and the Lyman-$\alpha$ forest baryon acoustic oscillation feature
• More accurate simulations with separate initial conditions for baryons and dark matter
• Hybrid Cosmological Simulations with Stream Velocities
• A Complete Catalogue of Dusty Supernova Remnants
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• How Density Environment Changes the Influence of the Dark Matter-Baryon Streaming Velocity on the Cosmological Structure Formation
• Signatures of First Stars in Galaxy Surveys: Multi-Tracer Analysis of the Supersonic Relative Velocity Effect and the Constraints from the BOSS Power Spectrum Measurements
• Constraining Warm Dark Matter and Pop III stars with the Global 21-cm Signal
• Swampland conjectures in hybrid metric-Palatini gravity
• The Supersonic Project: rotational effects of supersonic motions on the first structures in the Universe
• Large-scale variation in reionization history caused by Baryon-dark matter streaming velocity
• The AGORA High-resolution Galaxy Simulations Comparison Project. V: Satellite Galaxy Populations In A Cosmological Zoom-in Simulation of A Milky Way-mass Halo
• First Structure Formation under the Influence of Gas-Dark Matter Streaming Velocity and Density: Impact of the Baryons-trace-dark matter Approximation
• First estimate of the local value of the baryonic streaming velocity
• On the operation of the chemothermal instability in primordial star-forming clouds
• A Model-Insensitive Baryon Acoustic Oscillation Feature in the 21 cm Signal from Reionization
• The Supersonic Project: To cool or not to cool Supersonically Induced Gas Objects (SIGOs)?
• The First Billion Years in Seconds: An Effective Model for the 21-cm Signal with Population III Stars
• Dwarf galaxy formation with and without dark matter-baryon streaming velocities
• The high-redshift tail of stellar reionization in LCDM is beyond the reach of the low-$\ell$ CMB
• Formation of First Galaxies inside Density Peaks and Voids under the Influence of Dark Matter-Baryon Streaming Velocity, I: Initial Condition and Simulation Scheme
• The effect of Primordial Black Holes and streaming motions on structure formation
• Setting the Stage: Structures from Gaussian Random Fields
• The Supersonic Project: The eccentricity and rotational support of SIGOs and DM GHOSts
• Amplification of Magnetic Fields in a Primordial HII Region and Supernova
• Particle initialization effects on Lyman-$\alpha$ forest statistics in cosmological SPH simulations
• Aeos: Transport of Metals from Minihalos following Population III Stellar Feedback
• Relative baryon-dark matter velocities in cosmological zoom simulations
• Numerical Discreteness Errors in Multi-Species Cosmological N-body Simulations
• Effect of Separate Initial Conditions on the Lyman-$\alpha$ Forest in Simulations
• The temperature of IGM at high redshifts: shock heating and high mach problem
• Luminosity Bias (II): The Cosmic Web of the First Stars
• The Supersonic Project: SIGOs, a Proposed Progenitor to Globular Clusters, and their Connections to Gravitational Wave Anisotropies
• Cosmic voids and BAO with relative baryon-CDM perturbations