First detection of the Hubble variation correlation and its scale dependence

Understand

The sample variance due to our local density fluctuations in measuring our local Hubble-constant ($H_0$) can be reduced to the percentage level by choosing the Hubble-flow type Ia supernovae (SNe Ia) outside of the homogeneity scale.

• In this Letter, we have revealed a hidden trend in this one-percent $H_0$ variation both theoretically and observationally.
• We have derived for the first time our $H_0$ variation measured from any discrete sample of distant SNe Ia.
• We have also identified a residual linear correlation between our local $H_0$ fitted from different groups of SNe Ia and their ambient density contrasts of SN-host galaxies evaluated at a given scale.