Relative baryon-dark matter velocities in cosmological zoom simulations

Abstract

Supersonic relative motion between baryons and dark matter due to the decoupling of baryons from the primordial plasma after recombination affects the growth of the first small-scale structures. Large box sizes (greater than a few hundred Mpc) are required to sample the full range of scales pertinent to the relative velocity, while the effect of the relative velocity is strongest on small scales (less than a few hundred kpc). This separation of scales naturally lends itself to the use of `zoom' simulations, and here we present our methodology to self-consistently incorporate the relative velocity in zoom simulations, including its cumulative effect from recombination through to the start time of the simulation. We apply our methodology to a large-scale cosmological zoom simulation, finding that the inclusion of relative velocities suppresses the halo baryon fraction by $46$--$23$ per cent between $z=13.6$ and $11.2$, in qualitative agreement with previous works. In addition, we find that including the relative velocity delays the formation of star particles by $\sim 20\mathrm{Myr}$ Myr on average (of the order of the lifetime of a $\sim 9{\mathrm{M}}_{\odot }$ Population III star) and suppresses the final stellar mass by as much as $79$ per cent at $z=11.2$.

14 pages, 12 figures. Accepted for publication in MNRAS

References in corpus (13)

• Array Programming with NumPy
• Five-Year Wilkinson Microwave Anisotropy Probe (WMAP) Observations: Cosmological Interpretation
• CMasher: Scientific colormaps for making accessible, informative and 'cmashing' plots
• On the onset of galactic winds in quiescent star forming galaxies
• Supersonic Gas Streams Enhance the Formation of Massive Black Holes in the Early Universe
• Large-scale BAO signatures of the smallest galaxies
• The formation of direct collapse black holes under the influence of streaming velocities
• The formation and gas content of high redshift galaxies and minihalos
• On the signature of the baryon-dark matter relative velocity in the two and three-point galaxy correlation functions
• Globular Clusters and Dark Satellite Galaxies through the Stream Velocity
• Supersonic Relative Velocity between Dark Matter and Baryons: A Review
• 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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