The global 21-cm signal of a network of cosmic string wakes

Abstract

ABSTRACT In previous works, we discussed the 21-cm signature of a single cosmic string wake. However, the 21-cm brightness temperature is influenced by a network of cosmic string wakes, and not one single wake. In this work, we consider the signal from a network of wakes laid down during the matter era. We also improve on the previous calculation of a single wake signature. Finally, we calculate the enhancement of the global 21-cm brightness temperature due to a network of wakes and discuss its affects of the signal measured in the Wouthuysen–Field absorption trough. We estimated that for string tensions between 10−8 and 10−7 there would be between a 10 per cent and a factor of 2 enhancement in the signal.