Probing beyond the Epoch of Hydrogen Reionization with 21 Centimeter Radiation

By Benedetta Ciardi, P. Madau. 2003

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We use numerical simulations of hydrogen reionization by stellar sources in the context of ΛCDM cosmogonies to investigate the 21 (1 + z) cm radio signal expected from the diffuse intergalactic medium (IGM) prior to the epoch of reionization breakthrough at redshift zion. Two reionization scenarios are analyzed in detail: an "early reionization" case with zion ≈ 13, consistent with the recent discovery by the Wilkinson Microwave Anisotropy Probe (WMAP) satellite of a large optical depth to Thomson scattering, and a "late reionization" case with zion ≈ 8. It is a generic prediction of these models that the background of Lyα photons produced by the early generation of stars which ultimately ionize the universe will be sufficiently intense to make intergalactic neutral hydrogen visible against the cosmic microwave background during the "gray age," i.e., zion ≲ z ≲ 20. Depending on the redshift of reionization breakthrough, broad-beam observations at frequencies ≲150 MHz (below 100 MHz for the early reionization scenario) with the next generation of radio telescopes should reveal angular fluctuations in the sky brightness temperature in the range 5-20 mK (1 σ) on scales below 5'.

Subfields: Astronomy and Astrophysics, Nuclear and High Energy Physics

View Paper: https://www.semanticscholar.org/paper/db11ed372873ff92a3bd0f7ca37b047394cd722e

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Citations in the corpus

Radiation Backgrounds at Cosmic Dawn: X-Rays from Compact Binaries (2016, background): “…Lyα background photons to mix the hyperfine levels and of a pre-heating mechanism, such as X-ray radiation from the first galaxies or AGNs (e.g., Field 1958; Madau et al. 1997; Ciardi & Madau 2003; Chen & Miralda-Escudé 2004; Kuhlen et al. 2006; Furlanetto 2006; Pritchard & Furlanetto 2007).”
Early Reionization by Miniquasars (2003, background): “As recently discussed by Tozzi et al. (2000), Ciardi & Madau (2003), and Furlanetto, Sokasian, & Hernquist (2003), the fluctuations in 21 cm line induced by the ‘cosmic web’ that develops at early times in CDM-dominated cosmologies could be detected in emission against the CMB provided that: (a) at…”
Cosmological Parameter Estimation Using 21 cm Radiation from the Epoch of Reionization (2005, background): “Ciardi & Madau (2003) argue that around z 20, the first stars will produce a large enough background in Ly such that Tswill be coupled to the kinetic temperature of the gas through the Wouthuysen-Field effect.”
21 Centimeter Fluctuations from Cosmic Gas at High Redshifts (2003, background): “Recently, Ciardi & Madau (2003) and Furlanetto et al. (2003) used numerical simulations of reionization to estimate how the ﬂuctuations would behave during that epoch.”
SPECTROSCOPIC CONFIRMATION OF THREE z-DROPOUT GALAXIES AT z = 6.844–7.213: DEMOGRAPHICS OF Lyα EMISSION IN z ∼ 7 GALAXIES (2011, background): “This would suggest that reionization proceeds from high- to low-density environments (inside-out; e.g., Ciardi & Madau 2003; Sokasian et al. 2002; Iliev et al. 2006, c.f., Finlator et al. 2009) rather than from lowto high-density regions (outside-in; e.g., Gnedin 2000; Miralda-Escudé et al. 2000).”
The morphology of H ii regions during reionization (2006, background): “We also assume Ts TCMB in this section, likely a good approximation during the bulk of the reionization epoch (Ciardi & Madau 2003; Furlanetto 2006).”
Foreground simulations for the LOFAR-epoch of reionization experiment (2008, methodology): “Although Ts is calculated according to equation (3), we assume that Ts TCMB.”
Simulating cosmic reionization at large scales – II. The 21-cm emission features and statistical signals (2006, background): “We can compare our results to previously published reionization PDFs. Ciardi & Madau (2003) studied a 20/h Mpc simulation volume and presented the PDF at the resolution of their pixels z , much below the resolution of planned observations and the sizes we are addressing here, making a comparison dif”
A Method for Separating the Physics from the Astrophysics of High-Redshift 21 Centimeter Fluctuations (2004, background): “…through the universe, redshifted into the Lya resonance, and coupled Ts and Tk once again through the Wouthuysen-Field effect (Wouthuysen 1952; Field 1958), by which the two hyperfine states are mixed through the absorption and reemission of a Lya photon (Madau et al. 1997; Ciardi & Madau 2003).”
The GMRT Epoch of Reionization experiment: a new upper limit on the neutral hydrogen power spectrum at z≈ 8.6 (2010, background): “We have also considered the case where reheating of the IGM does not occur, so the spin temperature remains coupled to the kinetic temperature of the gas (Ciardi & Madau 2003).”
Simulations and Analytic Calculations of Bubble Growth during Hydrogen Reionization (2006, background): “At the redshifts we consider presently, the 21 cm excitation temperature is likely coupled to the gas temperature, and much larger than the temperature of the CMB (e.g. Furlanetto 2006; Chen & Miralda-Escude 2004; Ciardi & Madau 2003), TS >> TCMB, implying δT ∝ (1 + δs)xH .”
Foregrounds for observations of the cosmological 21 cm line - I. First Westerbork measurements of Galactic emission at 150 MHz in a low latitude field (2009, background): “Simulations indicate that the cosmological signal is expected to vary with redshift (Ciardi & Madau 2003; Mellema et al. 2006; Thomas et al. 2008).”
LOFAR: The LOw-Frequency ARray (2013, background): “It is generally acknowledged that the 21-cm emission line from neutral hydrogen at high redshifts is the most promising probe for studying the Cosmic Dawn and the EoR in detail (Field 1958; Madau et al. 1997; Ciardi & Madau 2003).”
The Evolution of the Intergalactic Medium (2015, methodology): “The grand hope of reionization aficionados is that the structures during reionization will be mapped using the 21 cm hyperfine transition of atomic hydrogen (Madau, Meiksin & Rees 1997; Ciardi & Madau 2003; Zaldarriaga, Furlanetto & Hernquist 2004).”
INTENSITY MAPPING WITH CARBON MONOXIDE EMISSION LINES AND THE REDSHIFTED 21 cm LINE (2011, methodology): “Alongside studies of the 21 cm signal from the EoR, it was pointed out that similar experiments could map large scale structure after reionization by detecting 21 cm emission from residual neutral hydrogen locked up in galaxies and damped Ly-α systems (Chang et al. 2008, Wyithe & Loeb 2007b).”
Inside-out or outside-in: the topology of reionization in the photon-starved regime suggested by Lyα forest data (2008, background): “…be a reasonable assumption once a significant fraction (a few 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…”