A cosmic string solution to the radio synchrotron background

Understand

We investigate the low-frequency spectral emission from a network of superconducting cosmic string loops in hopes of explaining the observed radio synchrotron background.

• After considering constraints from a variety of astrophysical and cosmological measurements, we identify a best-fit solution with string tension $G\mu \simeq 6.5 \times 10^{-12}$ and current $\mathcal{I} \simeq 2.5 \times 10^6$ GeV.
• This model yields a convincing fit to the data and may be testable in the near future by spectral distortion (TMS, BISOU) and 21 cm experiments (HERA, SKA, REACH).
• We also find that soft photon heating protects us against current constraints from global $21$ cm experiments.