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Borm, Julien Van; Corthouts, Jan; Philips, Richard

doi:10.1023/a:1005630824825

Cited by 4 publications

(2 citation statements)

References 11 publications

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“…Indeed, Agarwal et al (2012Agarwal et al ( , 2013 find that a large fraction of the SMBHs in the centers of galaxies today may have been seeded by SMSs. Strengthening these conclusions are other recent results which suggest that lower LW fluxes may be required for the formation of SMSs, due to a reduced role of H 2 self-shielding (Wolcott-Green et al 2011) and the presence of significant turbulence or magnetic fields (Van Borm & Spaans 2013).…”

Section: Introductionsupporting

confidence: 61%

The Biggest Explosions in the Universe

Johnson

2013

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Supermassive primordial stars are expected to form in a small fraction of massive protogalaxies in the early universe, and are generally conceived of as the progenitors of the seeds of supermassive black holes (BHs). Supermassive stars with masses of ∼ 55, 000 M ⊙ , however, have been found to explode and completely disrupt in a supernova (SN) with an energy of up to ∼ 10 55 erg instead of collapsing to a BH. Such events, ∼ 10, 000 times more energetic than typical SNe today, would be among the biggest explosions in the history of the universe. Here we present a simulation of such a SN in two stages. Using the RAGE radiation hydrodynamics code we first evolve the explosion from an early stage through the breakout of the shock from the surface of the star until the blast wave has propagated out to several parsecs from the explosion site, which lies deep within an atomic cooling dark matter (DM) halo at z ≃ 15. Then, using the GADGET cosmological hydrodynamics code we evolve the explosion out to several kiloparsecs from the explosion site, far into the low-density intergalactic medium. The host DM halo, with a total mass of 4 × 10 7 M ⊙ , much more massive than typical primordial star-forming halos, is completely evacuated of high density gas after 10 Myr, although dense metal-enriched gas recollapses into the halo, where it will likely form second-generation stars with metallicities of ≃ 0.05 Z ⊙ after 70 Myr. The chemical signature of supermassive star explosions may be found in such long-lived second-generation stars today.

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Section: Introductionsupporting

confidence: 61%

The Biggest Explosions in the Universe

Johnson

2013

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“…While an elevated LW radiation field is likely required to sufficiently suppress H2 cooling during the collapse of the gas (e.g. Bromm & Loeb 2003;Shang et al 2010;Van Borm & Spaans 2013;Visbal et al 2014a), the results of both semi-analytic models (e.g. Dijkstra et al 2008;Petri et al 2012;Agarwal et al 2012;Fernandez et al 2014;Ferrara et al 2014;Visbal et al 2014b) and cosmological simulations (Agarwal et al 2014) suggest that such fields may have been produced regularly in the early universe and therefore that DCBH formation may have been relatively common.…”

Section: Introductionmentioning

confidence: 99%

The impact of reionization on the formation of supermassive black hole seeds

Johnson¹,

Whalen²,

Agarwal³

et al. 2014

Monthly Notices of the Royal Astronomical Society

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Direct collapse black holes (DCBHs) formed from the collapse of atomically-cooled primordial gas in the early Universe are strong candidates for the seeds of supermassive BHs. DCBHs are thought to form in atomic cooling haloes in the presence of a strong molecule-dissociating, Lyman-Werner (LW) radiation field. Given that star forming galaxies are likely to be the source of the LW radiation in this scenario, ionizing radiation from these galaxies may accompany the LW radiation. We present cosmological simulations resolving the collapse of primordial gas into an atomic cooling halo, including the effects of both LW and ionizing radiation. We find that in cases where the gas is not self-shielded from the ionizing radiation, the collapse can be delayed by ∼ 25 Myr. When the ionized gas does collapse, the free electrons that are present catalyze H 2 formation. In turn, H 2 cooling becomes efficient in the center of the halo, and DCBH formation is prevented. We emphasize, however, that in many cases the gas collapsing into atomic cooling haloes at high redshift is self-shielding to ionizing radiation. Therefore, it is only in a fraction of such haloes in which DCBH formation is prevented due to reionization.

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Truly European: interlending and document supply in Belgium at the beginning of the twenty‐first century

Borm

Corthouts

2003

Interlending &Amp; Document Supply

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Belgium, one of the smaller European Union countries, has long since integrated its interlending and document supply in a truly European context and 20 per cent of all supplies come from the document supply centres of neighbouring countries. The Belgian electronic documentordering system, IMPALA, is the heart of the system. New ICT developments in communication technology will render traditional ILL and document supply partly obsolete by making available full text databases.

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Untitled

Cited by 4 publications

References 11 publications

The Biggest Explosions in the Universe

The Biggest Explosions in the Universe

The impact of reionization on the formation of supermassive black hole seeds

Truly European: interlending and document supply in Belgium at the beginning of the twenty‐first century

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