Cosmic String Interpretation of NANOGrav Pulsar Timing Data

Pulsar timing data used to provide upper limits on a possible stochastic gravitational wave background (SGWB). However, the NANOGrav Collaboration has recently reported strong evidence for common-spectrum process, which we interpret as SGWB in framework of cosmic strings. The signal would correspond string tension $G\mu \in (4 \times 10^{-11}, 10^{-10}) $ at 68% confidence level, with different frequency dependence from supermassive black hole mergers. produced by strings such values $G\mu$ be beyond reach LIGO, but could measured other planned and proposed detectors SKA, LISA, TianQin, AION-1km, AEDGE, Einstein Telescope Cosmic Explorer.