GAIA Cepheid parallaxes and 'Local Hole' relieve $H_0$ tension

Tom Shanks, Lucy Hogarth, Nigel Metcalfe

There is an $\approx 9\pm 2.5$\% tension between the value of Hubble's Constant, $H_0=67.4\pm 0.5$km\,s${}^{-1}$Mpc${}^{-1}$, implied by the {\it Planck} microwave background power spectr…