The history of star formation in a lcdm universe

By Volker Springel, Lars Hernquist Mpa, Harvard-CfA. 2002

322 citations recorded by the source corpus.

Employing hydrodynamic simulations of structure formation in a ⁄CDM cosmology, we study the history of cosmic star formation from the \dark ages" at redshift z » 20 to the present. In addition to gravity and ordinary hydrodynamics, our model includes radiative heating and cooling of gas, star formation, supernova feedback, and galactic winds. By making use of a comprehensive set of simulations on interlocking scales and epochs, we demonstrate numerical convergence of our results on all relevant halo mass scales, ranging from 10 8 to 10 15 h i1 Mfl. The predicted density of cosmic star formation, _ ‰?(z), is broadly consistent with measurements, given observational uncertainty. From the present epoch, _ ‰?(z) gradually rises by about a factor of ten to a peak at z » 5 i 6, which is beyond the redshift range where it has been estimated observationally. In our model, fully 50% of the stars are predicted to have formed by redshift z ’ 2:14, and are thus older than 10.4 Gyr, while only 25% form at redshifts lower than z ’ 1. The mean age of all stars at the present is about 9 Gyr. Our model predicts a total stellar density at z = 0 of ›? = 0:004, corresponding to about 10% of all baryons being locked up in long-lived stars, in agreement with recent determinations of the luminosity density of the Universe. We determine the \multiplicity function of cosmic star formation" as a function of redshift; i.e. the distribution of star formation with respect to halo mass. At redshifts around z ’ 10, star formation occurs preferentially in halos of mass 10 8 i10 10 h i1 Mfl, while at lower redshifts, the dominant contribution to _ ‰?(z) comes from progressively more massive halos. Integrating over time, we flnd that about 50% of all stars formed in halos less massive than 10 11:5 h i1 Mfl, with nearly equal contributions per logarithmic mass interval in the range 10 10 i 10 13:5 h i1 Mfl, making up » 70% of the total. We also brie∞y examine possible implications of our predicted star formation history for reionisation of hydrogen in the Universe. According to our model, the stellar contribution to the ionising background is expected to rise for redshifts z > 3, at least up to redshift z » 5, in accord with estimates from simultaneous measurements of the H and He opacities of the Lyman-fi forest. This suggests that the UV background will be dominated by stars for z > 4, provided that there are not signiflcantly more quasars at high-z than are presently known. We measure the clumping factor of the gas from the simulations and estimate the growth of cosmic HII regions, assuming a range of escape fractions for ionising photons. We flnd that the star formation rate predicted by the simulations is su‐cient to account for hydrogen reionisation by z » 6, but only if a high escape fraction close to unity is assumed.

Subfields: Astronomy and Astrophysics, Instrumentation

View Paper: https://www.semanticscholar.org/paper/6d409cbcca42ce2b8eeaa7e9aede90c60a57dd6a

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Citations in the corpus

The stellar masses of 25 000 galaxies at 0.2 ≤ z ≤ 1.0 estimated by the COMBO-17 survey (2006, methodology): “The dynamical aspects of CDM-based galaxy formation can by now be well described either by numerical ab-initio simulations (e.g. Springel & Hernquist 2003; Weinberg et al. 2004) or by semi-analytic modeling (Kauffmann et al. 1993; Cole et al. 1994; Cole et al. 2000; Somerville et al. 2001).”
Galaxy Evolution in Cosmological Simulations with Outflows II: Metallicities and Gas Fractions (2011, methodology): “Here we assume this density threshold is nH = 0.13 cm −3, which is a somewhat arbitrary choice motivated by resolution considerations (Springel & Hernquist 2003b).”
Supernova feedback in an inhomogeneous interstellar medium (2014, background): “These approximations include temporarily suppressing hydrodynamical interactions (e.g. Springel & Hernquist 2003; Oppenheimer & Davé 2006; Vogelsberger et al. 2013) or gas cooling (e.g. Stinson et al. 2006; Governato et al. 2007; Shen, Wadsley & Stinson 2010; Guedes et al. 2011) as kinetic or…”
The origin of the galaxy mass-metallicity relation and implications for galactic outflows (2007, methodology): “We found that the “constant wind” model as implemented by Springel & Hernquist (2003b) leads to poor agreement with observations at z ∼ 2, while our momentum-driven wind scalings naturally reproduce the slope and amplitude of the observed relation.”
Concordance models of reionization: implications for faint galaxies and escape fraction evolution (2012, background): “The clumping factor must be selected with care, since formal averages CHII ∼ 〈n2HII〉/〈nHII〉2 over simulation volumes yield large values ∼ 30 (e.g., Gnedin & Ostriker 1997; Springel & Hernquist 2003) that imply very demanding requirements on the ionizing sources.”
The morphology of H ii regions during reionization (2006, background): “Springel & Hernquist (2003) find that feedback from galactic winds suppresses star formation in the least massive systems relative to the more massive.”
An analytical model for the history of cosmic star formation (2002, methodology): “In Springel & Hernquist 2003b, we measured s(M , z) directly at different epochs from our set of hydrodynamic simulations.”
Introducing the Illustris Project: the evolution of galaxy populations across cosmic time (2014, methodology): “The local star formation time-scale in our model (Springel & Hernquist 2003a) is a function of gas density; hence, the overall star formation time-scale of a galaxy depends on the density distribution of its star-forming gas, which in turn is determined by dynamical, as well as feedback, processes.”
The properties of satellite galaxies in simulations of galaxy formation (2009, methodology): “This type of wind model has been widely used in hydrodynamic simulations of galaxy formation (e.g. Springel & Hernquist 2003a; Nagamine, Springel, & Hernquist 2004; Okamoto et al. 2008b).”
Moving mesh cosmology: the hydrodynamics of galaxy formation (2011, background): “…pure hydrodynamics other physical processes, such as star formation and associated feedback, are modelled in cosmological simulations, it is necessary to resolve all star-forming haloes with a sufficiently large number of resolution elements to reach convergent results (Springel & Hernquist 2003b).”
Stellar Feedback in Galaxies and the Origin of Galaxy-scale Winds (2011, background): “…lacking the ability to directly resolve the relevant feedback processes, put in winds ‘by hand’ by e.g. forcing an outflow rate that scales in a user-specified manner with the SFR or other parameters (Springel & Hernquist 2003a; Oppenheimer & Davé 2008; Sales et al. 2010; Genel et al. 2012).”
Feedback and the fundamental line of low-luminosity low-surface-brightness/dwarf galaxies (2002, background): “…be transferred to the gas in either bulk kinetic energy or thermal energy, but it can also be kept in reservoirs of other forms such as turbulence, which would amplify the feedback effects on the gas (e.g. Efstathiou 2000; Springel 2000; Thacker & Couchman 2000, 2001; Springel & Hernquist 2003a,b).”
Self-regulated star formation in galaxies via momentum input from massive stars (2011, methodology): “…the net stellar mass formed from cooled baryons exceeds that observed by an order of magnitude or more, particularly in lower mass haloes (e.g. Katz, Weinberg & Hernquist 1996; Somerville & Primack 1999; Cole et al. 2000; Springel & Hernquist 2003b; Kereš et al. 2009, and references therein).”
A UNIVERSAL, LOCAL STAR FORMATION LAW IN GALACTIC CLOUDS, NEARBY GALAXIES, HIGH-REDSHIFT DISKS, AND STARBURSTS (2011, unknown): “…law, equation (1) with ǫff ≈ 0.01, as one of the standard recipes in numerical simulations of star formation on galactic or cosmological scales (e.g. Springel & Hernquist 2003; Robertson & Kravtsov 2008; Gnedin et al. 2009; Bournaud et al. 2010; Teyssier et al. 2010; Ceverino et al. 2010; Agertz…”
Intracluster stars in simulations with active galactic nucleus feedback (2010, methodology): “Star formation and supernovae feedback were modelled with a subresolution multi-phase model for the interstellar medium as in Springel and Hernquist (2003a).”
Modelling feedback from stars and black holes in galaxy mergers (2004, background): “In particular, Springel & Hernquist (2003b) have shown that our coarse-graining procedure leads to a numerically converged estimate for the cosmic star formation history of the Universe (Hernquist & Springel 2003) that agrees well with low redshift observations.”
Bimodality of low-redshift circumgalactic O VI in non-equilibrium EAGLE zoom simulations (2016, methodology): “The main modifications to the entropy-conserving SPH implementation of the Gadget-3 code (Springel & Hernquist 2003a) comprise i) the pressure-entropy SPH formulation described by Hopkins (2013), ii) the artificial viscosity switch of Cullen & Dehnen (2010), iii) the artificial conduction switch of…”
Galaxies–intergalactic medium interaction calculation – I. Galaxy formation as a function of large-scale environment (2009, methodology): “The simulations of both Springel & Hernquist (2003b) and Oppenheimer & Davé (2006) use the multiphase ISM implementation of Springel & Hernquist (2003a) for gas in galaxies, as well as a different prescription for the generation of galactic winds.”