21 cm cosmology in the 21st century

By J. Pritchard, Abraham Loeb. Reports on progress in physics. Physical Society, 2011

780 citations recorded by the source corpus.

Imaging the Universe during the first hundreds of millions of years remains one of the exciting challenges facing modern cosmology. Observations of the redshifted 21 cm line of atomic hydrogen offer the potential of opening a new window into this epoch. This will transform our understanding of the formation of the first stars and galaxies and of the thermal history of the Universe. A new generation of radio telescopes is being constructed for this purpose with the first results starting to trickle in. In this review, we detail the physics that governs the 21 cm signal and describe what might be learnt from upcoming observations. We also generalize our discussion to intensity mapping of other atomic and molecular lines.

Subfields: Astronomy and Astrophysics, Instrumentation

View Paper: https://www.semanticscholar.org/paper/c831d74ecb40aceb5c5b52def19ff3957c4c4d39

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Citations in the corpus

Enhanced Global Signal of Neutral Hydrogen Due to Excess Radiation at Cosmic Dawn (2018, background): “It is described as T−1s = T−1r + xαT −1 α + xcT −1 K 1 + xα + xc , (3) where Tα is the color temperature of radiation around the Lyman-alpha transition, xα and xc are WFE and collisional coupling coefficients, which both follow a simple scaling ∝ T−1r (Pritchard & Loeb 2012).”
Inferring the astrophysics of reionization and cosmic dawn from galaxy luminosity functions and the 21-cm signal (2018, background): “…† andrei.mesinger@sns.it (AM) it a revolutionary probe of the early Universe (e.g. Hogan & Rees 1979; Scott & Rees 1990; Gnedin & Ostriker 1997; Madau et al. 1997; Shaver et al. 1999; Tozzi et al. 2000; Gnedin & Shaver 2004; Furlanetto et al. 2006; Morales & Wyithe 2010; Pritchard & Loeb 2012).”
21CMMC: an MCMC analysis tool enabling astrophysical parameter studies of the cosmic 21 cm signal (2015, background): “At the forefront of these will be the detection of the redshifted 21 cm spin-flip transition of neutral hydrogen (see e.g. Furlanetto et al. 2006b; Morales & Wyithe 2010; Pritchard & Loeb 2012) from several dedicated radio interferometers.”
Neutrino Mass Ordering from Oscillations and Beyond: 2018 Status and Future Prospects (2018, background): “…that of the CMB, which, for small frequencies and up to first order in perturbation theory, reads as Madau et al. (1997); Furlanetto et al. (2006); Pritchard and Loeb (2012); Furlanetto (2015) δTb(ν) ≃ 27 xHI (1+ δb) ( 1− TCMB TS )( 1 1+H−1∂vr/∂r ) ( 1+ z 10 )1/2 ( 0.15 mh2 )1/2 ( bh 2 0.023 )…”
The First Billion Years project: the escape fraction of ionizing photons in the epoch of reionization (2015, background): “Upcoming observations of the distribution of neutral hydrogen during reionisation provides an indirect way to test the escape fractions and reionisation sources that are favoured by our simulations (see e.g. Pritchard & Loeb 2012, for a review).”
On the detection of a cosmic dawn signal in the radio background (2021, methodology): “The instrument is cycled through a set of states while observing: equal time is spent with the receiver connected to (1) the antenna, (2) the reference load with calibration noise off and (3) the reference load with calibration noise on.”