Dark Matter Halo Environment for Primordial Star Formation

Abstract

We study the statistical properties (such as shape and spin) of high-z halos likely hosting the first (PopIII) stars with cosmological simulations including detailed gas physics. In the redshift range considered ($11<z<16$) the average sphericity is $<s>=0.3\pm 0.1$, and for more than 90% of halos the triaxiality parameter is $T\lesssim 0.4$, showing a clear preference for oblateness over prolateness. Larger halos in the simulation tend to be both more spherical and prolate: we find $s\propto M_h^{{\alpha }_s}$ and $T\propto M_h^{{\alpha }_T}$, with ${\alpha }_s\approx 0.128$ and ${\alpha }_T=0.276$ at z = 11. The spin distributions of dark matter and gas are considerably different at $z=16$, with the baryons rotating slower than the dark matter. At lower redshift, instead, the spin distributions of dark matter and gas track each other almost perfectly, as a consequence of a longer time interval available for momentum redistribution between the two components. The spin of both the gas and dark matter follows a lognormal distribution, with a mean value at z=16 of $<\lambda >=0.0184$, virtually independent of halo mass. This is in good agreement with previous studies. Using the results of two feedback models (MT1 and MT2) by McKee & Tan (2008) and mapping our halo spin distribution into a PopIII IMF, we find that at high-$z$ the IMF closely tracks the spin lognormal distribution. Depending on the feedback model, though, the distribution can be centered at $\approx 65M_{\odot }$ (MT1) or $\approx 140M_{\odot }$ (MT2). At later times, model MT1 evolves into a bimodal distribution with a second prominent peak located at $35-40M_{\odot }$ as a result of the non-linear relation between rotation and halo mass. We conclude that the dark matter halo properties might be a key factor shaping the IMF of the first stars.

10 pages, 6 figures, accepted for publication in MNRAS

References in corpus (63)

• Galactic Stellar and Substellar Initial Mass Function
• On the variation of the Initial Mass Function
• The cosmological simulation code GADGET-2
• Cosmological SPH simulations: A hybrid multi-phase model for star formation
• The Formation of the First Star in the Universe
• The Formation of the First Stars. I. The Primordial Star Forming Cloud
• Substructures in hydrodynamical cluster simulations
• Formation of Supermassive Black Holes
• The Shape of Dark Matter Halos: Dependence on Mass, Redshift, Radius, and Formation
• Simulations of Early Structure Formation: Primordial Gas Clouds
• Concentration, Spin and Shape of Dark Matter Haloes: Scatter and the Dependence on Mass and Environment
• The First Galaxies
• The spin and shape of dark matter haloes in the Millennium simulation of a LambdaCDM universe
• Formation of Primordial Stars in a LCDM Universe
• Simulations on a Moving Mesh: The Clustered Formation of Population III Protostars
• The Formation of the First Low-Mass Stars From Gas With Low Carbon and Oxygen Abundances
• The Formation and Fragmentation of Disks around Primordial Protostars
• Protostellar Feedback Halts the Growth of the First Stars in the Universe
• Internal and External Alignment of the Shapes and Angular Momenta of LCDM Halos
• Protostar Formation in the Early Universe
• Chemical enrichment of galaxy clusters from hydrodynamical simulations
• Galacticus: A Semi-Analytic Model of Galaxy Formation
• Rapid growth of high redshift black holes
• The formation of the first stars and galaxies
• Formation of the First Stars by Accretion
• The First Cosmic Structures and their Effects
• The Effect of Gas Cooling on the Shapes of Dark Matter Halos
• Protostellar Collapse with Various Metallicities
• The first stars: formation of binaries and small multiple systems
• The Formation of the First Stars II. Radiative Feedback Processes and Implications for the Initial Mass Function
• Low-Mass Relics of Early Star Formation
• Population III star formation in a Lambda CDM universe, I: The effect of formation redshift and environment on protostellar accretion rate
• The First Stars: Mass Growth Under Protostellar Feedback
• The Fate of the First Galaxies. II. Effects of Radiative Feedback
• The transition from population III to population II-I star formation
• Origin of Quasar Progenitors from the Collapse of Low-Spin Cosmological Perturbations
• Magnetic Fields in Population III Star Formation
• Evidence for a Triaxial Milky Way Dark Matter Halo from the Sagittarius Stellar Tidal Stream
• Metal and molecule cooling in simulations of structure formation
• Metal and molecule cooling in simulations of structure formation
• The Cusp/Core problem and the Secondary Infall Model
• The interplay between chemical and mechanical feedback from the first generation of stars
• On determining the shape of matter distributions
• Population III.1 and III.2 gamma-Ray Bursts: Constraints on the event rate for future radio and X-ray surveys
• The effects of baryons on the halo mass function
• Constraints on the IMF of the first stars
• Does Radiative Feedback by the First Stars Promote or Prevent Second Generation Star Formation?
• Ionization Front Instabilities in Primordial H II Regions
• First Structure Formation: A Simulation of Small Scale Structure at High Redshift
• Do Mergers Spin up Dark Matter Halos?
• Halo Shapes From Weak Lensing: The Impact of Galaxy--Halo Misalignment
• Constraints on the shapes of galaxy dark matter haloes from weak gravitational lensing
• Early structure formation in quintessence models and its implications for cosmic reionisation from first stars
• The correlation structure of dark matter halo properties
• Properties of Dark Matter Haloes and their Correlations: the Lesson from Principal Component Analysis
• Simulations of the formation and evolution of isolated dwarf galaxies - II. Angular momentum as a second parameter
• The onset of star formation in primordial haloes
• Pop. III stars from turbulent fragmentation at redshift ~ 11
• An MCMC Fitting Method for Triaxial Dark Matter Haloes
• Radiative feedback and cosmic molecular gas: numerical method
• Dissecting the spin distribution of Dark Matter halos
• Spin and structural halo properties at high redshift in a LCDM Universe
• Searching for the first stars with the Gaia mission

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• One Hundred First Stars : Protostellar Evolution and the Final Masses
• Formation of the First Stars
• Primordial Star Formation under the Influence of Far Ultraviolet Radiation: 1540 Cosmological Halos and the Stellar Mass Distribution
• Massive black hole factories: Supermassive and quasi-star formation in primordial halos
• Simulating cosmic metal enrichment by the first galaxies
• The Influence of Streaming Velocities on the Formation of the First Stars
• Formation sites of Population III star formation: The effects of different levels of rotation and turbulence on the fragmentation behavior of primordial gas
• Complex scalar field dark matter on galactic scales
• The First Stars: A Low-Mass Formation Mode
• Constraining the PopIII IMF with high-z GRBs
• Simulating the growth of Intermediate Mass Black Holes
• Detectability of the First Cosmic Explosions
• Probing the stellar initial mass function with high-$z$ supernovae
• Origin of Cosmic Chemical Abundances
• The Overlooked Potential of Generalized Linear Models in Astronomy - I: Binomial Regression
• Robust PCA and MIC statistics of baryons in early mini-haloes
• Statistical properties of mass, star formation, chemical content and rotational patterns in early z > 9 structures
• Feedback Limits to Maximum Seed Masses of Black Holes
• The seeds of supermassive black holes and the role of local radiation and metal spreading
• The formation of the primitive star SDSS J102915+172927: effect of the dust mass and the grain-size distribution
• Statistical properties of dark matter mini-haloes at z >= 15
• Metal enrichment signatures of the first stars on high-z DLAs
• Signatures of very massive stars: supercollapsars and their cosmological rate
• Shape and Spin of Minihaloes. II: The Effect of Streaming Velocities
• Shape and Spin of Minihaloes: From Large Scales to the Centres
• AMADA-Analysis of Multidimensional Astronomical Datasets
• Direct N-body simulations of rotating and extremely massive Population III star clusters