The effects of peculiar velocities in SN Ia environments on the local $H_0$ measurement

Understand

The discrepancy between estimates of the Hubble Constant ($H_0$) measured from local ($z \lesssim 0.1$) scales and from scales of the sound horizon is a crucial problem in modern cosmology.

• Peculiar velocities ($v_{pec}$) of standard candle distance indicators can systematically affect local $H_0$ measurements.
• We here use 2MRS galaxies to measure the local galaxy density field, finding a notable $z$ < 0.05 under-density in the SGC-6dFGS region of 27 $\pm$ 2 %.
• However, no strong evidence for a 'Local Void' pertaining to the full 2MRS sky coverage is found.