Signatures of modified gravity on the 21 cm power spectrum at reionisation

Journal Article · Tue Jan 01 04:00:00 EST 2013 · Journal of Cosmology and Astroparticle Physics

DOI:https://doi.org/10.1088/1475-7516/2013/01/003· OSTI ID:22279595

Brax, Philippe ^[1]; Clesse, Sébastien; Davis, Anne-Christine ^[2]

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1. Institut de Physique Théorique, CEA, IPhT, CNRS, URA 2306, F-91191 Gif/Yvette Cedex (France)
2. DAMTP, Centre for Mathematical Sciences, University of Cambridge, Wilberforce Road, Cambridge CB3 0WA (United Kingdom)

Scalar modifications of gravity have an impact on the growth of structure. Baryon and Cold Dark Matter (CDM) perturbations grow anomalously for scales within the Compton wavelength of the scalar field. In the late time Universe when reionisation occurs, the spectrum of the 21 cm brightness temperature is thus affected. We study this effect for chameleon-f(R) models, dilatons and symmetrons. Although the f(R) models are more tightly constrained by solar system bounds, and effects on dilaton models are negligible, we find that symmetrons where the phase transition occurs before z{sub *} ∼ 12 could be detectable for a scalar field range as low as 5kpc. For all these models, the detection prospects of modified gravity effects are higher when considering modes parallel to the line of sight where very small scales can be probed. The study of the 21 cm spectrum thus offers a complementary approach to testing modified gravity with large scale structure surveys. Short scales, which would be highly non-linear in the very late time Universe when structure forms and where modified gravity effects are screened, appear in the linear spectrum of 21 cm physics, hence deviating from General Relativity in a maximal way.

• OSTI ID: 22279595
• Journal Information: Journal of Cosmology and Astroparticle Physics, Journal Name: Journal of Cosmology and Astroparticle Physics Journal Issue: 01 Vol. 2013; ISSN 1475-7516
• Country of Publication: United States
• Language: English

Related Subjects

79 ASTRONOMY AND ASTROPHYSICS
ASTROPHYSICS
BARYONS
BRIGHTNESS
COMPTON WAVELENGTH
COSMOLOGY
DILATONS
GENERAL RELATIVITY THEORY
GRAVITATION
NONLINEAR PROBLEMS
NONLUMINOUS MATTER
PERTURBATION THEORY
PHASE TRANSFORMATIONS
SCALAR FIELDS
SCALARS
SOLAR SYSTEM
UNIVERSE