Early Cosmological H II/He III Regions and Their Impact on Second-Generation Star Formation

By Naoki Yoshida, S. Oh, T. Kitayama, L. Hernquist. 2006

169 citations recorded by the source corpus.

We present the results of three-dimensional radiation hydrodynamics simulations of the formation and evolution of early H II/He III regions around the first stars. Cooling and recollapse of the gas in the relic H II region is also followed in a full cosmological context, until second-generation stars are formed. We first carry out ray-tracing simulations of ionizing radiation transfer from the first star. Hydrodynamics is directly coupled with photoionization heating as well as radiative and chemical cooling. The photoionized hot gas is evacuated out of the host halo at a velocity of ~30 km s-1. This radiative feedback effect quenches further star formation within the halo for over tens to a hundred million years. We show that the thermal and chemical evolution of the photoionized gas in the relic H II region is remarkably different from that of a neutral primordial gas. Efficient molecular hydrogen production in the recombining gas enables it to cool to ~100 K, where fractionation of HD/H2 occurs. The gas further cools by HD line cooling down to a few tens of kelvins. Interestingly, at high redshifts (z > 10), the minimum gas temperature is limited by that of the cosmic microwave background with TCMB = 2.728(1 + z). The gas cloud experiences runaway collapse when its mass is ~40 M☉, which is significantly smaller than a typical clump mass of ~200-300 M☉ for early primordial gas clouds. We argue that massive, rather than very massive, primordial stars may form in the relic H II region. Such stars might be responsible for early metal enrichment of the interstellar medium from which recently discovered hyper-metal-poor stars were born.

Subfields: Astronomy and Astrophysics, Nuclear and High Energy Physics

View Paper: https://www.semanticscholar.org/paper/23dcd9c86b93245edfca0b3ef47a28556a09563d

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Citations in the corpus

Resolving the Formation of Protogalaxies. II. Central Gravitational Collapse (2007, background): “Negative feedback may occur from baryonic expulsion from host halos (Whalen et al. 2004; Kitayama et al. 2004; Yoshida et al. 2007; Abel et al. 2007) and halo photoevaporation (Susa & Umemura 2006; Whalen et al. 2008).”
Photodissociation of H2 in protogalaxies: modelling self‐shielding in three‐dimensional simulations (2011, methodology): “The “Six–Ray Approximation” Finally we consider one non–local method, variations of which have been implemented in simulations by, e.g., Yoshida et al. (2003, 2007) and Glover & Mac Low (2007a,b).”
Formation and evolution of primordial protostellar systems (2012, background): “…medium (IGM; e.g. Bromm, Kudritzki & Loeb 2001; Schaerer 2002; Alvarez, Bromm & Shapiro 2006; Abel, Wise & Bryan 2007; Johnson, Greif & Bromm 2007; Yoshida et al. 2007; Whalen et al. 2008; Greif et al. 2009), and the violent supernova explosions that marked their deaths enriched the primordial…”
ACCRETION ONTO THE FIRST STELLAR-MASS BLACK HOLES (2007, background): “They influenced subsequent structure formation through their UV radiation heating the surrounding gas and initiating reionization (Whalen et al. 2004; Kitayama et al. 2004; Alvarez et al. 2006; Johnson & Bromm 2007; Abel et al. 2007; Yoshida et al. 2007; Wise & Abel 2007, 2008).”
Primordial star formation under the influence of far ultraviolet radiation: 1540 cosmological haloes and the stellar mass distribution (2015, background): “In principle, one can simulate the evolution of such clouds and nearby H II regions by solving the transfer of EUV (hν > 13.6 eV) radiation (e.g., Yoshida et al. 2007).”
Formation of z~6 Quasars from Hierarchical Galaxy Mergers (2006, result): “We note that recent studies by Johnson & Bromm (2007), Abel et al. (2007), and Yoshida et al. (2007) show that H ii regions form around the first stars and that the halo gas would be photoionized, photoheated, and evacuated by the radiation feedback from the stars.”
The First Stellar Cluster (2007, background): “We therefore expect that fragmentation will also occur in full cosmological simulations, if these are continued beyond the formation of the very first stellar object (see e.g. Yoshida et al. 2007, for some preliminary evidence of this).”
Population III stars: hidden or disappeared? (2007, background): “…Machacek, Bryan, Abel 2003; Omukai & Yoshii 2003; Yoshida et al. 2003; Susa & Umemura 2006), HD chemistry (Nagakura & Omukai 2005; Greif & Bromm 2006; Johnson & Bromm 2006; Yoshida et al. 2007) and radiative transfer (Ciardi, Ferrara & Abel 2000; Ricotti, Gnedin & Shull 2001; Kitayama et al. 2001).”
Suppression of H2 Cooling in the Ultraviolet Background (2007, background): “— Baryonic expulsion from host halos (Whalen et al. 2004; Kitayama et al. 2004; Yoshida et al. 2007; Abel et al. 2007), photoevaporation (Susa & Umemura 2006), entropy floors (Oh & Haiman 2003).”
The First Stars (2012, background): “…H+2 was re-examined by Glover & Savin (2009), who showed that the collisional excitation rates cited by Galli & Palla (1998) and used as a basis for the fits given in Yoshida et al. (2007) were a factor of ten too large, and that if the correct rates are used, H+2 cooling is no longer important.”
ONE HUNDRED FIRST STARS: PROTOSTELLAR EVOLUTION AND THE FINAL MASSES (2013, background): “We solve chemical rate equations for 14 primordial species (e−, H, H+, H−, He, He+, He++, H2, H + 2 , D, D+, HD, HD+, HD−) as in Yoshida et al. (2006, 2007).”
COMPLETING THE CENSUS OF Lyα EMITTERS AT THE REIONIZATION EPOCH (2011, background): “These objects are plausible Population III candidates because of their extraordinarily large EW at high z, though they are expected to dominate at higher z (7 < z < 15), according to most model predictions (Johnson et al. 2008, Yoshida et al. 2007).”
The first galaxies : assembly, cooling and the onset of turbulence (2008, background): “This enormous flux of ionizing radiation could power H ii regions with radii of the order of 10 kpc, larger and longer-lived than the transient H ii regions of individual Pop III stars (Yoshida et al. 2007; Johnson et al. 2007a).”
Resolving the Formation of Protogalaxies. III. Feedback from the First Stars (2007, background): “In halos with masses <∼ 10 6 M⊙, the baryon fraction lowers to 5×10−3 ten million years after the star’s death without a SN (cf. Yoshida et al. 2007).”
THE MASS SPECTRUM OF THE FIRST STARS (2014, background): “…HD molecules, abundant H2 molecules are necessary since the HD molecules mainly form via the following reactions (Nakamura & Umemura 2002): D + H2 → H + HD D+ + H2 → H+ + HD In addition, it is known that the HD molecules are favored at low temperatures (Yoshida et al. 2007; Solomon & Woolf 1973).”
The Destruction of Cosmological Minihalos by Primordial Supernovae (2008, background): “…of 2500–5000 pc while H ii regions of less massive stars are confined to very small radii (<10 3 pc) by the high central densities deep in the halo (Whalen et al. 2004; Kitayama et al. 2004; Alvarez et al. 2006; Abel et al. 2007; Johnson et al. 2007; Yoshida et al. 2007; Wise & Abel 2007a, 2007b).”
THE BIRTH OF A GALAXY: PRIMORDIAL METAL ENRICHMENT AND STELLAR POPULATIONS (2010, methodology): “…can be included by utilizing our ray tracing framework or other approximate methods that calculate the H2 column density using the local Sobolev length (Wolcott-Green et al. 2011) or only integrating along Cartesian axes or random lines of sight (Yoshida et al. 2003, 2007; Glover & Mac Low 2007).”
Production of dust by massive stars at high redshift (2011, background): “The formation of the second generation of stars (Pop III.2) is influenced bythe radiative and mechanical feedback effects of the first stars and is found to be delayed babout∼ 200 Myr (e.g., Johnson et al, 2007; Yoshida et al, 2007a).”