Evolution of the 21 cm signal throughout cosmic history

By J. Pritchard, Abraham Loeb. 2008

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The potential use of the redshifted 21 cm line from neutral hydrogen for probing the epoch of reionization is motivating the construction of several low-frequency interferometers. There is also much interest in the possibility of constraining the initial conditions from inflation and the nature of the dark matter and dark energy by probing the power spectrum of density perturbations in three dimensions and on smaller scales than probed by the microwave background anisotropies. Theoretical understanding of the 21 cm signal has been fragmented into different regimes of physical interest. In this paper, we make the first attempt to describe the full redshift evolution of the 21 cm signal between 0 < z < 300. We include contributions to the 21 cm signal from fluctuations in the gas density, temperature, and neutral fraction, as well as the Lya flux, and allow for a post-reionization signal from damped Lya systems. Our comprehensive analysis provides a useful foundation for optimizing the design of future arrays whose goal is to separate the particle physics from the astrophysics, either by probing the peculiar velocity distortion of the 21 cm power spectrum, or by extending the 21 cm horizon to z ≥ 25 before the first galaxies had formed, or to z ≤ 6 when the residual pockets of hydrogen trace large-scale structure.

Subfields: Astronomy and Astrophysics, Nuclear and High Energy Physics

View Paper: https://www.semanticscholar.org/paper/aceac53cc6d00b9f0c6da729ad95ecc61d23337f

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Citations in the corpus

The evolution of CMB spectral distortions in the early Universe (2011, background): “…of baryonic matter and radiation leads to a large difference in the CMB and electron temperature (Zeldovich et al. 1968) withTe < Tγ, which is also very important for the formation of the global 21cm signal from the epoch of reionization(e.g., see Pritchard & Loeb 2008, and references therein).”
Upper Limits on the 21 cm Epoch of Reionization Power Spectrum from One Night with LOFAR (2017, background): “…al. 2014; Watkinson & Pritchard 2014) and its power spectrum as a function of redshift (e.g Morales & Hewitt 2004; Bharadwaj & Ali 2005; Barkana & Loeb 2005; McQuinn et al. 2006; Bowman et al. 2006; Pritchard & Furlanetto 2007; Jelić et al. 2008; Harker et al. 2009, 2010; Pritchard & Loeb 2008).”
Stellar black holes at the dawn of the universe (2011, background): “…one heats the neutral IGM earlier by boosting fX, which implies that temperature fluctuations are suppressed during the later stages of reionization, which improves the prospects for extracting cosmological information from the 21 cm background (Pritchard & Furlanetto 2007; Pritchard & Loeb 2008).”
21 cm cosmology in the 21st century (2011, background): “Diagonal lines show Tfg(ν), the foreground temperature reduced by a factor ranging from 10−3 − 10−9 to indicate the level of foreground removal required to detect the signal [78].”
LATE-TIME COSMOLOGY WITH 21 cm INTENSITY MAPPING EXPERIMENTS (2014, background): “…(IM) methodology makes it possible to efficiently survey extremely large volumes (Battye et al. 2004, 2013; McQuinn et al. 2006; Loeb & Wyithe 2008; Pritchard & Loeb 2008; Wyithe & Loeb 2008; Chang et al. 2008; Mao et al. 2008; Wyithe et al. 2008; Peterson et al. 2009; Bagla et al. 2010; Seo et…”
Reionization and the Cosmic Dawn with the Square Kilometre Array (2012, methodology): “As the 21cm fluctuations evolve as a function of redshift, so does the power spectrum making it important to measure it at different redshifts (Pritchard & Loeb 2008).”
Reionization and Cosmology with 21-cm Fluctuations (2009, background): “The fluctuations and evolution of the kinetic and spin temperatures of HI are frontier issues in theoretical studies of the EoR (e.g. Pritchard & Furlanetto 2007, Pritchard & Loeb 2008).”
Inside-out or outside-in: the topology of reionization in the photon-starved regime suggested by Lyα forest data (2008, background): “…percent) of the volume/mass has been ionized (Scott & Rees 1990; Tozzi et al. 2000; Ciardi & Madau 2003; Barkana & Loeb 2005; Sethi 2005; Furlanetto 2006; Furlanetto, Oh, & Briggs 2006; see Pritchard & Loeb 2008 for an extensive recent discussion of the expectedevolution of the spin temperature).”
Inflation and the scale dependent spectral index: prospects and strategies (2010, background): “Such experiments can be focussed either at moderate redshifts z = 7 − 25, where the effects of reionization and the first stars will serve as a major contaminant [76], or at redshifts z = 25 − 50, before star formation has begun.”