Pulsar timing arrays within rotating and expanding Universe

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. Therefore, no gravitational wave background is necessary to elucidate the pulsar timing data.
Comment: 10 pages, 3 figures, 19 references; v2: one reference added