Hints of FLRW breakdown from supernovae

A 10% difference in the scale for the Hubble parameter constitutes a clear problem for cosmology. Here, considering angular distribution of type Ia supernovae (SN) within the Pantheon compilation and working within flat ?CDM cosmology, we observe a correlation between higher H0 and the CMB dipole direction, confirming our previous results for strongly lensed quasars [Classical Quantum Gravity 38, 184001 (2021)CQGRDG0264-938110.1088/1361-6382/ac1a81]. Concretely, we record a ~1 km/s/Mpc variation in H0 at antipodal points on the sky within the Pantheon sample, which is evident in the Low z subsample (z?0.075) and gets enhanced by higher redshift SN. Our work raises the possibility that we may be at the precision required to probe anisotropic Hubble expansions, while providing a concrete prediction for future inferences of H0.