The Growth of H II Regions During Reionization

By S. Furlanetto, M. Zaldarriaga, L. Hernquist. 2004

416 citations recorded by the source corpus.

Recently, there has been a great deal of interest in understanding the reionization of hydrogen in the intergalactic medium (IGM). One of the major outstanding questions is how this event proceeds on large scales. Motivated by numerical simulations, we develop a model for the growth of H II regions during the reionization era. We associate ionized regions with large-scale density fluctuations and use the excursion set formalism to model the resulting size distribution. We then consider ways in which to characterize the morphology of ionized regions. We show how to construct the power spectrum of fluctuations in the neutral hydrogen field. The power spectrum contains definite features from the H II regions that should be observable with the next generation of low-frequency radio telescopes through surveys of redshifted 21 cm emission from the reionization era. Finally, we also consider statistical descriptions beyond the power spectrum and show that our model of reionization qualitatively changes the distribution of neutral gas in the IGM.

Subfields: Astronomy and Astrophysics, Nuclear and High Energy Physics

View Paper: https://www.semanticscholar.org/paper/bbcc1762c7f2b8a1483923a7077cc3ed65165b18

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Citations in the corpus

COSMIC MICROWAVE BACKGROUND CONSTRAINTS ON THE DURATION AND TIMING OF REIONIZATION FROM THE SOUTH POLE TELESCOPE (2011, methodology): “…2005; McQuinn et al. 2007b; Choudhury et al. 2009; Crociani et al. 2011). several groups to develop much more CPU efficient, approximate algorithms (Furlanetto et al. 2004; Zahn et al. 2005b, 2007; Mesinger & Furlanetto 2007; Geil & Wyithe 2008; Alvarez et al. 2009; Choudhury et al. 2009; Thomas…”
ON LYMAN-LIMIT SYSTEMS AND THE EVOLUTION OF THE INTERGALACTIC IONIZING BACKGROUND (2011, background): “First, models predict large temporal variance between when different ∼ 30 cMpc locations in the IGM were ionized, with the majority of the gas ionized over an interval of ∆z & 3 (Furlanetto et al. 2004; McQuinn et al. 2007).”
Signatures of X-rays in the early Universe (2012, methodology): “This code uses perturbation theory (PT) to generate the density and velocity fields, and PT plus the excursion-set formalism of Furlanetto et al. (2004) to generate the ionization fields.”
Inferring the astrophysics of reionization and cosmic dawn from galaxy luminosity functions and the 21-cm signal (2018, methodology): “Then, 21cmfast estimates the ionization field from the evolved IGM density field by comparing the cumulative number of ionizing photons to the number of neutral atoms plus cumulative recombinations within spheres of decreasing radii (e.g. Furlanetto et al. 2004).”
Studying reionization with Lyα emitters (2007, background): “In reality, the HII regions can be much larger throughout reionization than this simple model predicts owing to the clustering of highredshift sources (e.g., Sokasian et al. 2003; Furlanetto et al. 2004a,b).”
Simulating Cosmic Reionization at Large Scales I: the Geometry of Reionization (2005, background): “Over the years many analytical approaches to modelling reionization have been proposed (e.g. Shapiro et al. 1994; Haiman& Holder 2003; Wyithe & Loeb 2003; Furlanetto et al. 2004; Iliev et al. 2005a).”
21-cm fluctuations from inhomogeneous X-ray heating before reionization (2006, methodology): “By this point, the filling fraction of H II regions probably becomes significant and ionization fluctuations begin to dominate the 21-cm signal (Furlanetto et al. 2004). z zr : after reionization, any remaining 21-cm signal originates from overdense regions of collapsed neutral hydrogen.”
Charting the parameter space of the global 21-cm signal (2016, background): “According to current understanding, reionization happens inside out, proceeding first in the dense regions containing most of the sources (Barkana & Loeb 2004; Furlanetto et al. 2004; Iliev et al. 2006).”
Enhanced Global Signal of Neutral Hydrogen Due to Excess Radiation at Cosmic Dawn (2018, background): “The 21 cm spatial fluctuations have been extensively studied theoretically (Furlanetto et al. 2004; Morales & Wyithe 2010), but this faint signal is yet to be detected, largely due to very bright foreground contaminants, such as Galactic synchrotron, supernovae remnants, free-free emission and…”
EVIDENCE FOR PopIII-LIKE STELLAR POPULATIONS IN THE MOST LUMINOUS Lyα EMITTERS AT THE EPOCH OF REIONIZATION: SPECTROSCOPIC CONFIRMATION (2015, background): “…are particularly important to test and refine models of galaxy formation and evolution (e.g. Vogelsberger et al. 2014; Schaye et al. 2015) and to study the epoch of re-ionisation (e.g. Shapiro et al. 1994; Sokasian et al. 2004; Furlanetto et al. 2004; McQuinn et al. 2006; Iliev et al. 2006).”
The morphology of H ii regions during reionization (2006, methodology): “Analytic models provide a convenient and intuitive framework to understand the structure of reionization (Furlanetto et al. 2004b, 2005; Zahn et al. 2006).”
Simulating cosmic reionization at large scales – II. The 21-cm emission features and statistical signals (2006, methodology): “…by considering small enough regions (thus achieving the high resolution required) either during the Cosmic Dark Ages (Shapiro et al. 2005; Kuhlen et al. 2006) or during reionization (Carilli et al. 2002; Ciardi & Madau 2003; Gnedin & Shaver 2004; Furlanetto et al. 2004; Valdés et al. 2006).”
Comparison of reionization models: radiative transfer simulations and approximate, seminumeric models (2010, methodology): “We extend the Furlanetto et al. (2004) scheme to 3D realizations by requiring that an ionized simulation cell at coordinate x meet the criteria (c.f. Zahn et al. 2005; Mesinger & Furlanetto 2007). fcoll(x, z, R) ≥ ζ−1 , (1) where ζ is some efficiency parameter and fcoll is the fraction of mass…”
The GMRT Epoch of Reionization experiment: a new upper limit on the neutral hydrogen power spectrum at z≈ 8.6 (2010, methodology): “This general patchy topology is well motivated by theory and simulations ⋆ Email:paciga@astro.utoronto.ca † Email:pen@cita.utoronto.ca (e.g. Furlanetto et al. 2004; Iliev et al. 2006; McQuinn et al. 2007; Zahn et al. 2007; see Trac & Gnedin 2009 for a review) though the exact properties are poorly…”