The numerical frontier of the high-redshift Universe

Greif, Thomas H.

doi:10.1186/s40668-014-0006-2

Cited by 113 publications

(85 citation statements)

References 757 publications

(885 reference statements)

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“…In particular, primordial stars in the mass range 140 − 260M explode as pair-instability supernovae (Heger et al, 2003), liberating enough energy to effectively empty the mini-halos of gas. Lower-mass Pop III stars would still damp energy, having a significant impact on the ambient medium if they form in clusters, as it is likely (Greif, 2015), owing to the shallow potential wells of mini-halos. X-ray radiative feedback also suppresses further fueling of gas, leading effectively to accretion rates as small as ∼ 1% of the Eddington rate, and thus stifling the growth of the BH seed well below the expectations from the Eddingtonlimited accretion model considered above (Alvarez et al, 2009;Jeon et al, 2012).…”

Section: Formation Of Massive Black Hole Seedsmentioning

confidence: 99%

Formation of the First Stars and Black Holes

et al. 2020

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KeywordsAbstract We review the current status of knowledge concerning the early phases of star formation during cosmic dawn. This includes the first generations of stars forming in the lowest mass dark matter halos in which cooling and condensation of gas with primordial composition is possible at very high redshift (z > 20), namely metal-free Population III stars, and the first generation of massive black holes forming at such early epochs, the socalled black hole seeds. The formation of black hole seeds as end states of the collapse of Population III stars, or via direct collapse scenarios, is discussed. In particular, special emphasis is given to the physics of supermassive stars as potential precursors of direct collapse black holes, in light of recent results of stellar evolution models, and of numerical simulations of the early stages of galaxy formation. Furthermore, we discuss the role of the cosmic radiation produced by the early generation of stars and black holes at high redshift in the process of reionization.

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Section: Formation Of Massive Black Hole Seedsmentioning

confidence: 99%

Formation of the First Stars and Black Holes

et al. 2020

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“…The birth of the first, so called Population III (Pop III), stars marks the transition from the 'Dark Ages' of the Universe to the complex structure we can observe today (Bromm 2013;Loeb & Furlanetto 2013;Greif 2015). These Pop III stars synthesise the first heavy elements, thus enabling the formation of subsequent generations of stars, contribute to the early reionisation of the Universe, and might provide seeds for supermassive black holes (for reviews, see Barkana & Loeb 2007; Volonteri & Bellovary ⋆ E-mail: hartwig@iap.fr 2012; Karlsson et al 2013).…”

Section: Introductionmentioning

confidence: 99%

Constraining the primordial initial mass function with stellar archaeology

Hartwig

Bromm

Klessen

et al. 2015

Monthly Notices of the Royal Astronomical Society

114

103

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We present a new near-field cosmological probe of the initial mass function (IMF) of the first stars. Specifically, we constrain the lower-mass limit of the Population III (Pop III) IMF with the total number of stars in large, unbiased surveys of the Milky Way. We model the early star formation history in a Milky Way-like halo with a semi-analytic approach, based on Monte-Carlo sampling of dark matter merger trees, combined with a treatment of the most important feedback mechanisms. Assuming a logarithmically flat Pop III IMF and varying its low mass limit, we derive the number of expected survivors of these first stars, using them to estimate the probability to detect any such Pop III fossil in stellar archaeological surveys. Following our analysis, the most promising region to find possible Pop III survivors is the stellar halo of the Milky Way, which is the best target for future surveys. We find that if no genuine Pop III survivor is detected in a sample size of 4 × 10 6 (2 × 10 7 ) halo stars with wellcontrolled selection effects, then we can exclude the hypothesis that the primordial IMF extended down below 0.8M ⊙ at a confidence level of 68% (99%). With the sample size of the Hamburg/ESO survey, we can tentatively exclude Pop III stars with masses below 0.65M ⊙ with a confidence level of 95%, although this is subject to significant uncertainties. To fully harness the potential of our approach, future large surveys are needed that employ uniform, unbiased selection strategies for high-resolution spectroscopic follow-up.

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“…Cosmological hydrodynamical simulations have been utilised to study the formation of Pop III stars (e.g. Stacy et al 2010;Clark et al 2011;Greif et al 2012;Hirano et al 2014;Bromm 2013;Greif 2015), but the IMF remains highly uncertain.…”

Section: Introductionmentioning

confidence: 99%

Limits on Population III star formation in minihaloes implied byPlanck

Visbal

Haiman

Bryan

2015

Mon. Not. R. Astron. Soc.

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Recently, Planck measured a value of the cosmic microwave background (CMB) optical depth due to electron scattering of τ = 0.066 ± 0.016. Here we show that this low value leaves essentially no room for an early partial reionisation of the intergalactic medium (IGM) by high-redshift Population III (Pop III) stars, expected to have formed in low-mass minihaloes. We perform semi-analytic calculations of reionisation which include the contribution from Pop II stars in atomic cooling haloes, calibrated with high-redshift galaxy observations, and Pop III stars in minihaloes with feedback due to Lyman-Werner (LW) radiation and metal enrichment. We find that without LW feedback or prompt metal enrichment (and assuming a minihalo escape fraction of 0.5) the Pop III star formation efficiency cannot exceed ∼ a few × 10 −4 , without violating the constraints set by Planck data. This excludes massive Pop III star formation in typical 10 6 M ⊙ minihaloes. Including LW feedback and metal enrichment alleviates this tension, allowing large Pop III stars to form early on before they are quenched by feedback. We find that the total density of Pop III stars formed across cosmic time is 10 4−5 M ⊙ Mpc −3 and does not depend strongly on the feedback prescription adopted. Additionally, we perform a simple estimate of the possible impact on reionisation of X-rays produced by accretion onto black hole remnants of Pop III stars. We find that unless the accretion duty cycle is very low ( 0.01), this could lead to an optical depth inconsistent with Planck.

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The numerical frontier of the high-redshift Universe

Cited by 113 publications

References 757 publications

Formation of the First Stars and Black Holes

Formation of the First Stars and Black Holes

Constraining the primordial initial mass function with stellar archaeology

Limits on Population III star formation in minihaloes implied byPlanck

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