A response to Rubin & Heitlauf: "Is the expansion of the universe accelerating? All signs still point to yes"

Understand

We have shown (Colin et al., 2019) that the acceleration of the Hubble expansion rate inferred from Type Ia supernovae (SNe Ia) is, at $3.9\sigma$ significance, a dipole approximately aligned with the CMB dipole, while its monopole component, which can be interpreted as due to a Cosmological Constant or dark energy, is consistent with zero at $1.4\sigma$.

• This has been challenged by Rubin & Heitlauf (2019) who assert that the dipole arises because we made an incorrect assumption about the SNe Ia light-curve parameters (viz.
• took them to be sample- and redshift independent), and did not allow for the motion of the Solar system (w.r.t.
• the 'CMB frame' in which the CMB dipole supposedly vanishes).