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arXiv · 1310.4176

High redshift signatures in the 21 cm forest due to cosmic string wakes

Hiroyuki Tashiro·Toyokazu Sekiguchi·Joseph Silk
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Abstract

Cosmic strings induce minihalo formation in the early universe. The resultant minihalos cluster in string wakes and create a "21 cm forest" against the cosmic microwave background (CMB) spectrum. Such a 21 cm forest can contribute to angular fluctuations of redshifted 21 cm signals integrated along the line of sight. We calculate the root-mean-square amplitude of the 21 cm fluctuations due to strings and show that these fluctuations can dominate signals from minihalos due to primordial density fluctuations at high redshift ($z \gtrsim 10$), even if the string tension is below the current upper bound, $G μ< 1.5 \times 10^{-7}$. Our results also predict that the Square Kilometre Array (SKA) can potentially detect the 21 cm fluctuations due to strings with $G μ\approx 7.5 \times 10^{-8}$ for the single frequency band case and $4.0 \times 10^{-8}$ for the multi-frequency band case.

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Hiroyuki Tashiro, Toyokazu Sekiguchi, Joseph Silk. 2013-10-15. High redshift signatures in the 21 cm forest due to cosmic string wakes. https://doi.org/10.1088/1475-7516%2F2014%2F01%2F013

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