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Hydrodynamic Response of the Intergalactic Medium to Reionization
- Source :
- The Astrophysical Journal
- Publication Year :
- 2020
-
Abstract
- The intergalactic medium is expected to clump on scales down to $10^4-10^8$ M$_{\odot}$ before the onset of reionization. The impact of these small-scale structures on reionization is poorly understood despite the modern understanding that gas clumpiness limits the growth of H II regions. We use a suite of radiation-hydrodynamics simulations that capture the $\sim 10^4$ $M_\odot$ Jeans mass of unheated gas to study density fluctuations during reionization. Our simulations track the complex ionization and hydrodynamical response of gas in the wake of ionization fronts. The clumping factor of ionized gas (proportional to the recombination rate) rises to a peak value of $5-20$ approximately $\Delta t = 10$ Myr after ionization front passage, depending on the incident intensity, redshift, and degree to which the gas had been pre-heated by the first X-ray sources. The clumping factor reaches its relaxed value of $\approx 3$ by $\Delta t = 300$ Myr. The mean free path of Lyman-limit photons evolves in unison, being up to several times shorter in un-relaxed, recently reionized regions compared to those that were reionized much earlier. Assessing the impact of this response on the global reionizaton process, we find that un-relaxed gaseous structures boost the total number of recombinations by $\approx 50$ % and lead to spatial fluctuations in the mean free path that persist appreciably for several hundred million years after the completion of reionization.<br />Comment: Matches published version
- Subjects :
- Cosmology and Nongalactic Astrophysics (astro-ph.CO)
Photon
Cosmic web
010504 meteorology & atmospheric sciences
Mean free path
FOS: Physical sciences
Hydrodynamical simulation
Astrophysics::Cosmology and Extragalactic Astrophysics
Astrophysics
Approx
01 natural sciences
Reionization
Radiative transfer simulation
Settore FIS/05 - Astronomia e Astrofisica
Ionization
0103 physical sciences
Astrophysics - Cosmology and Nongalactic Astrophysic
010303 astronomy & astrophysics
Astrophysics::Galaxy Astrophysics
Intergalactic medium
0105 earth and related environmental sciences
Physics
Astronomy and Astrophysics
Plasma
Astrophysics - Astrophysics of Galaxies
Redshift
13. Climate action
Space and Planetary Science
Astrophysics of Galaxies (astro-ph.GA)
Intensity (heat transfer)
Astrophysics - Cosmology and Nongalactic Astrophysics
Subjects
Details
- ISSN :
- 15384357
- Database :
- OpenAIRE
- Journal :
- The Astrophysical Journal
- Accession number :
- edsair.doi.dedup.....0cf199d2384bfa77f6665aea33629eb9
- Full Text :
- https://doi.org/10.3847/1538-4357/ab9f2f