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Properties of Intergalactic Filaments at z = 2 and Implications for the Evolution of Galaxies

Abstract : We now understand theoretically that galaxy evolution involves inflows of “cold” gas from the cosmic web. But corresponding models grow galaxies with amounts of baryons larger than observed galaxies. To overcome this issue, theorists focus on making star formation inefficient by massively blowing gas out of star-forming disks. I explore a different road, investigating processes that may moderate gas accretion onto disks. We present a phenomenological scenario where gas accretion flows – if it is shocked – become biphasic and, as a result, turbulent. In this framework, we show that the formation of warm, turbulent clouds, embedded in a hot component, occurs in the important mass range of ∼ 10^11 − 10^13 Msun, where the bulk of stars have formed in galaxies. Gas accreted from intergalactic filaments (IGF) may eventually lose coherence and mix with the ambient halo gas. The direct interaction between galaxy feedback and accretion streams is thus more likely. Moderating the accretion efficiency may help to alleviate a number of significant challenges in theoretical galaxy formation. Using the code Ramses, I performed a zoom-in simulation and extracted the results for a particular accreting IGF into a halo of ∼ 3 10^11 Msun at z ∼ 2. I investigate the gas thermodynamics and structuration, along and across the filament, with respect to dark matter. I study several key quantities as they evolve along the filament and derive a refined paradigm to study filaments, as well as consequences regarding their fate after entering a halo. I finally make use of these results to extrapolate gas processes that the simulation may not have captured accurately.
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https://tel.archives-ouvertes.fr/tel-01679690
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Submitted on : Wednesday, January 10, 2018 - 10:37:07 AM
Last modification on : Friday, May 29, 2020 - 4:01:59 PM
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  • HAL Id : tel-01679690, version 1

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Nicolas Cornuault. Properties of Intergalactic Filaments at z = 2 and Implications for the Evolution of Galaxies. Astrophysics [astro-ph]. Université Pierre et Marie Curie - Paris VI, 2017. English. ⟨NNT : 2017PA066208⟩. ⟨tel-01679690⟩

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