Cosmological Parameter Estimation Using 21 cm Radiation from the Epoch of Reionization

By M. McQuinn, Oliver Zahn, M. Zaldarriaga, L. Hernquist, S. Furlanetto. 2005

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A number of radio interferometers are currently being planned or constructed to observe 21 cm emission from reionization. Not only will such measurements provide a detailed view of that epoch, but, since the 21 cm emission also traces the distribution of matter in the universe, this signal can be used to constrain cosmological parameters. The sensitivity of an interferometer to the cosmological information in the signal may depend on how precisely the angular dependence of the 21 cm three-dimensional power spectrum can be measured. Using an analytic model for reionization, we quantify all the effects that break the spherical symmetry of the three-dimensional 21 cm power spectrum. We find that upcoming observatories will be sensitive to the 21 cm signal over a wide range of scales, from larger than 100 to as small as 1 comoving Mpc. Next, we consider three methods to measure cosmological parameters from the signal: (1) direct fitting of the density power spectrum to the signal, (2) using only the velocity field fluctuations in the signal, and (3) looking at the signal at large enough scales that all fluctuations trace the density field. With the foremost method, the first generation of 21 cm observations should moderately improve existing constraints on cosmological parameters for certain low-redshift reionization scenarios, and a 2 yr observation with the second-generation interferometer MWA5000 in combination with the CMB telescope Planck could improve constraints on Ωw, Ωmh2, Ωbh2, Ων, ns, and αs. If the universe is substantially ionized by z ~ 12 or if spin temperature fluctuations are important, we show that it will be difficult to place competitive constraints on cosmological parameters with any of the considered methods.

Subfields: Astronomy and Astrophysics, Atomic and Molecular Physics, and Optics

View Paper: https://www.semanticscholar.org/paper/f6c3b0c0ad20d47069861a08d761507b17210455

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Citations in the corpus

The GMRT Epoch of Reionization experiment: a new upper limit on the neutral hydrogen power spectrum at z≈ 8.6 (2010, background): “In the future 21 cm tomography has the potential to add strong constraints on cosmological parameters (e.g., McQuinn et al. 2006; Cooray et al. 2008; Mao et al. 2008; Furlanetto et al. 2009; Masui et al. 2010).”
21 cm cosmology in the 21st century (2011, background): “The effect of the configuration of the antennae is encoded in the number density of baselines n⊥(k) that observe a mode with transverse wavenumber k⊥ [146].”
A simulation-calibrated limit on the H i power spectrum from the GMRT Epoch of Reionization experiment (2013, background): “The distribution during the transition can be used to constrain cosmological parameters (McQuinn et al. 2006; Cooray, Li & Melchiorri 2008; Mao et al. 2008; Furlanetto et al. 2009; Pandolfi et al. 2011) and deduce the nature of the first ionizing sources themselves (Datta et al. 2012; Iliev et al.…”
FOUR FUNDAMENTAL FOREGROUND POWER SPECTRUM SHAPES FOR 21 cm COSMOLOGY OBSERVATIONS (2012, background): “…are smooth in frequency and thus separable from the nearly spherical EoR signal in principle (all emission near k‖ = 0, Morales et al. 2006; McQuinn et al. 2006), the effect of chromatic instrument responses, imperfect foreground models, and/or imperfect calibration conspire to throw this…”
Inside-out or outside-in: the topology of reionization in the photon-starved regime suggested by Lyα forest data (2008, methodology): “These studies range from radiative transfer simulation generally performed by post-processing the density field of DM simulations (Ciardi, Ferrara, & White 2003; Iliev et al. 2006b; Mellema et al. 2006; Iliev et al. 2007; McQuinn et al. 2006; McQuinn etal.”
The Evolution of the Intergalactic Medium (2015, methodology): “Some contributions to the sinks include photoevaporating minihalos (defined as halos below the threshold to cool atomically) and other thermally relaxing gaseous structures (Iliev, Shapiro & Raga 2005; Ciardi et al. 2006; McQuinn et al. 2006).”
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).”
Reionization and Cosmology with 21-cm Fluctuations (2009, background): “However McQuinn et al. (2006) found that planned low frequency arrays like MWA and LOFAR will not be sensitive to the µ4 term, and so could only provide useful cosmological constraints in a situation where density fluctuations dominate the 21 cm PS.”
21CMMC: an MCMC analysis tool enabling astrophysical parameter studies of the cosmic 21 cm signal (2015, methodology): “The thermal noise PS is computed at each uv-cell according to the following (e.g. Morales 2005; McQuinn et al. 2006; Pober et al. 2014), ∆2N(k) ≈ X2Y k3 2π2 Ω′ 2t T 2sys, (5) where X2Y is a cosmological conversion factor between observing bandwidth, frequency and comoving distance units, Ω′ is a…”
A SENSITIVITY AND ARRAY-CONFIGURATION STUDY FOR MEASURING THE POWER SPECTRUM OF 21 cm EMISSION FROM REIONIZATION (2011, methodology): “…(u, v, η)-mode, and the factor of two in the denominator comes from the explicit inclusion of two orthogonal polarizations to measure the total unpolarized signal.9 This equation differs from the derivations given in Morales (2005) and McQuinn et al. (2006) by only this polarization factor.”
21cmfast: a fast, seminumerical simulation of the high‐redshift 21‐cm signal (2010, background): “Preliminary studies therefore concluded that redshift space distortions would only be noticeable before reionization and in its early stages (McQuinn et al. 2006, MF07).”
OPENING THE 21 cm EPOCH OF REIONIZATION WINDOW: MEASUREMENTS OF FOREGROUND ISOLATION WITH PAPER (2013, neutral): “We 14 Derivations of equation 1 in Morales (2005), McQuinn et al. (2006), and Parsons et al. (2012a), relate ΩB to an effective cosmological volume, using a top-hat primary beam or effective area as a pedagogical tool to simplify the result.”
Inferring the astrophysics of reionization and cosmic dawn from galaxy luminosity functions and the 21-cm signal (2018, methodology): “First, we generate the thermal noise PS at each uv cell according to (e.g. Morales 2005; McQuinn et al. 2006; Pober et al. 2014): ∆2N(k) ≈ X 2Y k3 2π2 Ω′ 2t T2sys, (24) where XY2 is a scalar factor converting observed bandwidths and solid angles to comoving distance, Ω′ is a beamdependent factor…”
Foreground simulations for the LOFAR-epoch of reionization experiment (2008, background): “Measurements of the 21-cm signal can also help to constrain the cosmological parameters independently (McQuinn et al. 2006).”