NANOGrav signal from magnetohydrodynamic turbulence at the QCD phase transition in the early Universe

The NANOGrav collaboration has recently reported evidence for the existence of a stochastic gravitational wave background in 1-100 nHz frequency range. We argue that such could have been produced by magneto-hydrodynamic (MHD) turbulence at QCD scale. From measurement one can infer magnetic field parameters: comoving strength close to microGauss and correlation length 10\% Hubble radius phase transition epoch. point out turbulent decay non-helical with parameters leads recombination epoch, which would be sufficiently strong provide solution tension problem, as proposed. also show MHD interpretation signal tested via measurements relic voids large scale structure, gamma-ray telescopes like CTA.