Pulsar timing arrays within rotating and expanding Universe

Abstract

Recent measurements of the four pulsar timing arrays were interpreted as a signal of the low frequency stochastic gravitational wave background. We show that the amplitude and angular correlations of pulsar timing residuals can be interpreted as a consequence of the vortical geodetic motions of pulsar's photons within rotating and expanding Universe. The resulting angular correlation curves are similar to the Hellings-Downs curve and the observed amplitude allows the estimate of the vorticity of the Universe. We show that the estimated vorticity is compatible with the observed rotation of the CMB polarization vector.