A Method for Separating the Physics from the Astrophysics of High-Redshift 21 Centimeter Fluctuations

By R. Barkana, Abraham Loeb. 2004

216 citations recorded by the source corpus.

Fluctuations in the 21 cm brightness from cosmic hydrogen at redshifts z ≳ 6 have their source in the primordial density perturbations from inflation, as well as the radiation from galaxies. We propose a method to separate these components based on the angular dependence of the 21 cm fluctuation power spectrum. Peculiar velocities increase the power spectrum by a factor of ~2 compared with density fluctuations alone and introduce an angular dependence in Fourier space. The resulting angular structure relative to the line of sight facilitates a simple separation of the power spectrum into several components, permitting an unambiguous determination of the primordial power spectrum of density fluctuations, and of the detailed properties of all astrophysical sources of 21 cm fluctuations. We also demonstrate that angular multipoles are not useful for measuring large-scale power, and thus, theoretical predictions should focus on the three-dimensional power spectrum of 21 cm fluctuations.

Subfields: Astronomy and Astrophysics, Nuclear and High Energy Physics

View Paper: https://www.semanticscholar.org/paper/665593a746a7549702a998419bf4183e038b06c6

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Citations in the corpus

Simulating cosmic reionization at large scales – II. The 21-cm emission features and statistical signals (2006, background): “One should note that during the earliest stage of reionization, when sources were few and could only affect their local environments this assumption might not hold (Barkana & Loeb 2005b; Chuzhoy & Shapiro 2005), but such effects are still difficult to implement in simulations.”
21cmfast: a fast, seminumerical simulation of the high‐redshift 21‐cm signal (2010, methodology): “(24) C© 2010 The Authors, MNRAS 411, 955–972 Monthly Notices of the Royal Astronomical Society C© 2010 RAS Downloaded from https://academic.oup.com/mnras/article-abstract/411/2/955/1273635 by guest on 30 July 2018 Following Barkana & Loeb (2005b), we truncate the sum at nmax = 23, and use their Popu”
THE PRECISION ARRAY FOR PROBING THE EPOCH OF RE-IONIZATION: EIGHT STATION RESULTS (2009, methodology): “The most incisive probe of EoR is direct observation of the neutral IGM using the hydrogen 21cm line (Furlanetto et al. 2006; Barkana & Loeb 2005a).”
FOREGROUND CONTAMINATION IN INTERFEROMETRIC MEASUREMENTS OF THE REDSHIFTED 21 cm POWER SPECTRUM (2008, background): “…signal will be composed of contributions (due to velocity field and other astrophysical effects) from modes that are modulated according to powers of µ ≡ k̂ · n̂, where µ is the cosine of the angle between the line of sight and the wavevector (Kaiser 1987; Barkana & Loeb 2005; McQuinn et al. 2006).”
21-cm fluctuations from inhomogeneous X-ray heating before reionization (2006, methodology): “Noting that in Fourier space δ∂v =−µ2δ (Bharadwaj & Ali 2004), where µ is the angle between the line of sight and the wavevector k of the Fourier mode, we may use equation (5) to form the power spectrum (Barkana & Loeb 2005a) PTb (k, µ) = Pµ0 (k) + µ2 Pµ2 (k) + µ4 Pµ4 (k).”
The global 21-centimeter background from high redshifts (2006, methodology): “Cosmological measurements, spin temperature fluctuations (Barkana & Loeb 2005b; Pritchard & Furlanetto 2006), minihaloes (Iliev et al. 2002; Furlanetto & Oh 2006) and reionization itself must all be placed in their proper contexts, and this is a first step in that direction.”
The morphology of H ii regions during reionization (2006, background): “Equation (6) (as well as our calculations) neglects redshift-space distortions, which can enhance the signal (Barkana & Loeb 2005).”
The physics of the intergalactic medium (2007, background): “Such measurements could probe the structure of an inflationary potential and induced non-gaussian fluctuations (Barkana and Loeb, 2005; Bharadwaj and Ali, 2004; Loeb and Zaldarriaga, 2004; McQuinn et al., 2006; Pillepich et al., 2007).”
LATE-TIME COSMOLOGY WITH 21 cm INTENSITY MAPPING EXPERIMENTS (2014, methodology): “…algorithm, it should be possible to suppress them to such a level that the cosmological signal can be extracted in an unbiased way (Oh & Mack 2003; Barkana & Loeb 2005; Santos et al. 2005; Morales et al. 2006, 2012; Wang et al. 2006; Gleser et al. 2008; Jelić et al. 2008; Liu et al. 2009, 2014;…”
Observational Constraints on Cosmic Reionization (2006, background): “These objects are capable of ionizing large volumes at high-redshift, and could have played an important role in the early reionization of the IGM, depending on their currently ill-constained space density (Panagia et al. 2005; Barkana & Loeb 2005c).”
Science with the Murchison Widefield Array (2012, methodology): “The dependence on δ traces the development of the cosmic web (Scott & Rees 1990), while the velocity factor creates line-of-sight distortions that can be used to separate different components of the signal 3http://eor.berkeley.edu 4http://www.lofar.org (Barkana & Loeb 2005).”
Cosmological Parameter Estimation Using 21 cm Radiation from the Epoch of Reionization (2005, background): “Recently, Barkana & Loeb (2005a) showed that redshift-space distortions from peculiar velocities allow for the decomposition of the observed 21 cm three-dimensional (3D) power spectrum into terms that are proportional to 0, 2, and 4, where is the cosine of the angle between a mode k and the line of…”
21 cm Tomography with Foregrounds (2005, methodology): “…be a valuable tool for quantifying how redshift space distortions (whereby the peculiar velocity of the gas breaks the one-to-one correspondence between redshift and frequency) can be exploited to separate the effects of the matter power spectrum from the ‘‘gastrophysics’’ (Barkana & Loeb 2005a).”
Wouthuysen-Field coupling strength and application to high-redshift 21-cm radiation (2005, background): “(54) The source emissivity is modeled following Barkana & Loeb (2005b) by the equation ǫ(ν, z) = ǫb(ν) Ωb mpΩm d dt ∫ f⋆(M, t)Mn(M, t)dM, (55) where M is the relevant halo mass, n(M, t) is the comoving number density of halos at proper time t per unit mass, f⋆(M, t) is the fraction of the baryons…”
Neutrino Mass Ordering from Oscillations and Beyond: 2018 Status and Future Prospects (2018, background): “…| www.frontiersin.org 29 October 2018 | Volume 5 | Article 36 fundamental cosmology (Scott and Rees, 1990; Tozzi et al., 2000; Iliev et al., 2002; Barkana and Loeb, 2005a,b; McQuinn et al., 2006; Santos and Cooray, 2006; Bowman et al., 2007; Mao et al., 2008; Visbal et al., 2009; Clesse et al.,…”