Current models of the observable consequences of cosmic reionization and their detectability

• Main Authors: Ilian T. Iliev, Garrelt Mellema, Ue-li Pen, J. Richard Bond, Paul R. Shapiro
• Other Authors: The Pennsylvania State University CiteSeerX Archives
• Format: Text
• Language: English
• Published: 2008
• Subjects: Key words; H II regions—high-redshift—galaxies; formation—intergalactic medium—; South Pole; South pole
• Online Access: http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.338.1684; http://arxiv.org/pdf/astro-ph/0702099v2.pdf

A number of large current experiments aim to detect the signatures of the Cosmic Reionization at redshifts z> 6. Their success depends crucially on understanding the character of the reionization process and its observable consequences and designing the best strategies to use. We use large-scale simulations of cosmic reionization to evaluate the reionization signatures at redshifted 21-cm and small-scale CMB anisotropies in the best current model for the background universe, with fundamental cosmological parameters given by WMAP 3-year results (WMAP3). We find that the optimal frequency range for observing the “global step ” of the 21-cm emission is 120-150 MHz, while statistical studies should aim at 140-160 MHz, observable by GMRT. Some strongly-nongaussian brightness features should be detectable at frequencies up to ∼ 190 MHz. In terms of sensitivity-signal trade-off relatively low resolutions, corresponding to beams of at least a few arcminutes, are preferable. The CMB anisotropy signal from the kinetic Sunyaev-Zel’dovich effect from reionized patches peaks at tens of µK at arcminute scales and has an rms of ∼ 1µK, and should be observable by the Atacama Cosmology Telescope and the South Pole Telescope. We discuss the various observational issues and the uncertainties involved, mostly related to the poorly-known reionization parameters and, to a lesser extend, to the uncertainties in the background cosmology.