Primordial star formation under the influence of far ultraviolet radiation: 1540 cosmological haloes and the stellar mass distribution

By S. Hirano, T. Hosokawa, Naoki Yoshida, K. Omukai, H. Yorke. 2015

225 citations recorded by the source corpus.

We perform a large set of cosmological simulations of early structure formation and follow the formation and evolution of 1540 star-forming gas clouds to derive the mass distribution of primordial stars. The star formation in our cosmological simulations is characterized by two distinct populations, the so-called Population III.1 stars and primordial stars formed under the influence of far ultraviolet (FUV) radiation (Population III.2D stars). In this work, we determine the stellar masses by using the dependences on the physical properties of star-forming cloud and/or the external photodissociating intensity from nearby primordial stars, which are derived from the results of two-dimensional radiation hydrodynamic simulations of protostellar feedback. The characteristic mass of the Pop III stars is found to be a few hundred solar masses at z ~ 25, and it gradually shifts to lower masses with decreasing redshift. At high redshifts z > 20, about half of the star-forming gas clouds are exposed to intense FUV radiation and thus give birth to massive Pop III.2D stars. However, the local FUV radiation by nearby Pop III stars becomes weaker at lower redshifts, when typical Pop III stars have smaller masses and the mean physical separation between the stars becomes large owing to cosmic expansion. Therefore, at z < 20, a large fraction of the primordial gas clouds host Pop III.1 stars. At z =< 15, the Pop III.1 stars are formed in relatively cool gas clouds due to efficient radiative cooling by H_2 and HD molecules; such stars have masses of a few x 10 Msun. Since the stellar evolution and the final fate are determined by the stellar mass, Pop III stars formed at different epochs play different roles in the early universe.

Subfields: Astronomy and Astrophysics

View Paper: https://www.semanticscholar.org/paper/acad73c821e8a0e622a5a248fcd3071562ff6bb2

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In Astronomy and Astrophysics

1. Volker Bromm
2. S. Glover
3. Ralf Klessen
4. John H. Wise
5. A. Ferrara
6. Tom Abel
7. Zoltán Haiman
8. A. Stacy

Citations in the corpus

• Modeling the Radio Background from the First Black Holes at Cosmic Dawn: Implications for the 21 cm Absorption Amplitude (2018, background): “Such Pop-III stars are expected to form with masses of ∼10–103Me (Abel et al. 2002; Bromm et al. 2002; Yoshida et al. 2008; Stacy et al. 2010; Greif et al. 2011a; Hirano et al. 2015) in molecular cooling halos with Tvir104 K (Haiman et al. 1996; Abel et al. 1997; Tegmark et al. 1997).”
• GALAXY PROPERTIES AND UV ESCAPE FRACTIONS DURING THE EPOCH OF REIONIZATION: RESULTS FROM THE RENAISSANCE SIMULATIONS (2016, background): “The shape and characteristic mass of the Pop III initial mass function (IMF) is weakly constrained, but it is most probably top-heavy (e.g., Abel et al. 2002; Susa et al. 2014; Hirano et al. 2015).”
• Building up the Population III initial mass function from cosmological initial conditions (2016, methodology): “Hirano et al. (2015) use the primordial cloud characteristics to estimate the maximum Pop III mass for a larger number of minihaloes, finding a distribution with two peaks at ∼ 25 and 250 M⊙.”
• A Comprehensive Study of Galaxies at z ∼ 9–16 Found in the Early JWST Data: Ultraviolet Luminosity Functions and Cosmic Star Formation History at the Pre-reionization Epoch (2022, background): “Indeed in the early universe, the IMF is expected to be more top-heavy because of a lower metallicity or a higher CMB temperature (e.g., Omukai et al. 2005; Chon et al. 2022), resulting in a higher Jeans mass, especially for Population III stellar populations (e.g., Hirano et al. 2014, 2015).”
• FORMATION OF MASSIVE PRIMORDIAL STARS: INTERMITTENT UV FEEDBACK WITH EPISODIC MASS ACCRETION (2015, background): “103 M (see also Susa et al. 2014; Hirano et al. 2015, hereafter HR15).”
• Titans of the early Universe: The Prato statement on the origin of the first supermassive black holes (2018, result): “Cosmological simulations for the formation of the first stars show that Pop III stars can also be very massive, M∗ ≈ 10–1 000M (Hosokawa et al. 2011; Hirano et al. 2014, 2015), a prediction that is consistent with the Pop III IMF constraints inferred with Milky Way halo stars (de Bennassuti et al.…”