Formation Criteria and the Mass of Secondary Population Iii Stars

Susa, Hajime; Umemura, Masayuki; Hasegawa, Kenji

doi:10.1088/0004-637x/702/1/480

Cited by 24 publications

(27 citation statements)

References 77 publications

(107 reference statements)

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“…The sign of the feedback depends on various parameters, such as the state of the collapse and the distance to the source. If a halo is close to an ionizing source or has not yet collapsed to high densities, the halo may be photoevaporated, while in other cases the halo may survive and continue to collapse Kitayama et al , 2001Susa et al 2009;O'Shea et al 2005;Mesinger et al 2006Mesinger et al , 2009Whalen et al 2008aWhalen et al , 2010Hasegawa et al 2009). Whalen & Norman (2008) and Vasiliev et al (2012b) also showed that shadow and thin-shell instabilities may develop in the ionization fronts.…”

Section: Ionizing Radiationmentioning

confidence: 99%

The numerical frontier of the high-redshift Universe

Greif

2015

Comput. Astrophys.

113

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The first stars are believed to have formed a few hundred million years after the big bang in so-called dark matter minihalos with masses ∼ 10 6 M . Their radiation lit up the Universe for the first time, and the supernova explosions that ended their brief lives enriched the intergalactic medium with the first heavy elements. Influenced by their feedback, the first galaxies assembled in halos with masses ∼ 10 8 M , and hosted the first metal-enriched stellar populations. In this review, I summarize the theoretical progress made in the field of high-redshift star and galaxy formation since the turn of the millennium, with an emphasis on numerical simulations. These have become the method of choice to understand the multi-scale, multi-physics problem posed by structure formation in the early Universe. In the first part of the review, I focus on the formation of the first stars in minihalos -in particular the post-collapse phase, where disk fragmentation, protostellar evolution, and radiative feedback become important. I also discuss the influence of additional physical processes, such as magnetic fields and streaming velocities. In the second part of the review, I summarize the various feedback mechanisms exerted by the first stars, followed by a discussion of the first galaxies and the various physical processes that operate in them.

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Section: Ionizing Radiationmentioning

confidence: 99%

The numerical frontier of the high-redshift Universe

Greif

2015

Comput. Astrophys.

113

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“…But these models do not include the photoevaporation of the halo by the star prior to its explosion. Studies have shown that ionizing UV radiation from nearby Pop III stars can ablate the outer layers of the halo in supersonic flows and expose its interior to the IGM (Shapiro et al 2004;Iliev et al 2005;O'Shea et al 2005;Susa & Umemura 2006;Susa 2007;Hasegawa et al 2009;Susa et al 2009;Whalen et al 2010). The dense core casts a cylindrical shadow that is eventually crushed down into the axis of the halo by thermal pressure forces in the surrounding ionized gas.…”

Section: Introductionmentioning

confidence: 99%

How the First Stars Regulated Star Formation. II. Enrichment by Nearby Supernovae

Chen

Whalen

Wollenberg

et al. 2017

ApJ

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Metals from Population III (Pop III) supernovae led to the formation of less massive Pop II stars in the early universe, altering the course of evolution of primeval galaxies and cosmological reionization. There are a variety of scenarios in which heavy elements from the first supernovae were taken up into second-generation stars, but cosmological simulations only model them on the largest scales. We present small-scale, high-resolution simulations of the chemical enrichment of a primordial halo by a nearby supernova after partial evaporation by the progenitor star. We find that ejecta from the explosion crash into and mix violently with ablative flows driven off the halo by the star, creating dense, enriched clumps capable of collapsing into Pop II stars. Metals may mix less efficiently with the partially exposed core of the halo, so it might form either Pop III or Pop II stars. Both Pop II and III stars may thus form after the collision if the ejecta do not strip all the gas from the halo. The partial evaporation of the halo prior to the explosion is crucial to its later enrichment by the supernova.

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“…We note that for star formation to be suppressed by the photoionizing background during reionization, the minihalo must be subjected to the radiation before it reaches advanced stages of collapse, as an ionization front passing through a dense minihalo may act to induce star formation, not to prevent it (e.g. Ahn & Shapiro 2007; Whalen et al 2008a; Susa, Umemura & Hasegawa 2009). Therefore, we make the simple, conservative assumption that the gas collapsing into minihaloes with masses higher than M minihalo = 10 6 M ⊙ [(1 + z )/10] −3/2 , corresponding to virial temperature T vir ∼ 2 × 10 3 K (see e.g.…”

Section: Conditions For Population III Star Formation After Reionizmentioning

confidence: 99%

Population III star clusters in the reionized Universe

Johnson¹

2010

Monthly Notices of the Royal Astronomical Society

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In reionized regions of the Universe, gas can only collapse to form stars in dark matter (DM) haloes which grow to be sufficiently massive. If star formation is prevented in the minihalo progenitors of such DM haloes at redshifts z≳ 20, then these haloes will not be self‐enriched with metals and so may host Population (Pop) III star formation. We estimate an upper limit for the abundance of Pop III star clusters which thus form in the reionized Universe, as a function of redshift. Depending on the minimum DM halo mass for star formation, between of the order of 1 and of the order of 1000, Pop III star clusters per square degree may be observable at 2 ≲z≲ 7. Thus, there may be a sufficient number density of Pop III star clusters for detection in surveys such as the Deep‐Wide Survey (DWS) to be conducted by the James Webb Space Telescope. We predict that Pop III clusters formed after reionization are most likely to be found at z≳ 3 and within ∼40 arcsec (∼1 Mpc comoving) of DM haloes with masses of ∼1011 M⊙, the descendants of the haloes at z∼ 20 which host the first galaxies that begin reionization. However, if star formation is inefficient in the haloes hosting Pop III clusters due to the photoionizing background radiation, these clusters may not be bright enough for detection by the Near‐Infrared Camera which will conduct the DWS. None the less, if the stellar initial mass function (IMF) is top‐heavy the clusters may have sufficiently high luminosities in both Lyα and He iiλ1640 to be detected and for constraints to be placed on the Pop III IMF. While a small fraction of DM haloes with masses as high as ∼109 M⊙ at redshifts z≲ 4 are not enriched due to star formation in their progenitors, external metal enrichment due to galactic winds is likely to preclude Pop III star formation in a large fraction of otherwise unenriched haloes, perhaps even preventing star formation in pristine haloes altogether after reionization is complete at z∼ 6.

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Formation Criteria and the Mass of Secondary Population Iii Stars

Cited by 24 publications

References 77 publications

The numerical frontier of the high-redshift Universe

The numerical frontier of the high-redshift Universe

How the First Stars Regulated Star Formation. II. Enrichment by Nearby Supernovae

Population III star clusters in the reionized Universe

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