2019ApJ...875..145K

We use the largest sample to date of spectroscopic supernova (SN) Ia distances and redshifts to look for evidence in the Hubble diagram of large-scale outflows caused by local voids suggested to exist at z < 0.15. Our sample combines data from the Pantheon sample with the Foundation survey, and the most recent release of light curves from the Carnegie Supernova Project, to create a sample of 1295 SNe over a redshift range of 0.01 < z < 2.26. We make use of an inhomogeneous and isotropic Lemaitre-Tolman-Bondi metric to model a void in the SN Ia distance-redshift relation. We conclude that the SN luminosity distance-redshift relation is inconsistent at the 4-5σ confidence level with large local underdensities (| δ| > 20 % , where the density contrast δ = Δρ/ρ) proposed in some galaxy count studies, and find no evidence of a change in the Hubble constant corresponding to a void with a sharp edge in the redshift range 0.023 < z < 0.15. With an empirical precision of σ_H0_=0.60 % , we conclude that the distance ladder measurement is not affected by local density contrasts, in agreement with a cosmic variance of σ_H0_=0.42 % , predicted from simulations of large-scale structure. Given that uncertainty in the distance ladder value is σ_H0_=2.2 % , this does not affect the Hubble tension. We derive a 5σ constraint on local density contrasts on scales larger than 69Mpc h^–1 of | δ| < 27 % . The presence of local structure does not appear to impede the possibility of measuring the Hubble constant to 1% precision.