Gravitational waves from global cosmic strings and cosmic archaeology

Global cosmic strings are predicted in many motivated extensions to the Standard Model of particle physics, with close connections axion dark matter physics. Recent studies suggest that, although subdominant relative Goldstone emission, gravitational wave (GW) signals from global can be detectable current and planned GW detectors such as LIGO, LISA, DECIGO/BBO, ET/CE AEDGE/AION, well pulsar timing arrays PPTA, NANOGrav SKA. This work is an extensive, updated study on GWs a string network, taking into account most recent developments related subject. The main analysis based analytical Velocity-dependent One-Scale (VOS) model calibrated simulation results, which provides generic protocol for calculations details given. We also demonstrate how signal influenced variations baseline model: this includes considering uncertainties parameters potential deviation conventional VOS prediction (i.e. scaling behavior) suggested by some results. Furthermore, we investigated detail effect non-standard cosmology (e.g. early domination or kination) new species strings. that frequency spectrum background used probe history prior Big Bang nucleosynthesis (BBN) primordial age) up temperature $T\sim 10^8$ GeV.