Consistency of Pantheon+supernovae with a large-scale isotropic universe

We investigate the possible anisotropy of the universe using data on the most up-to-date type Ia supernovae,i.e.,the Pantheon+compilation.We fit the full Pantheon+data with the dipole-modulated ΛCDM model and find that the data are well consistent with a null dipole.We further divide the full sample into several subsamples with different high-redshift cutoffs zc.It is shown that the dipole appears at the 2σ confidence level only if z_(c)≤0.1,and in this redshift region,the dipole is very stable,almost independent of the specific value of zc.For z_(c)=0.1,the dipole amplitude is D=1.0_(-0.4^(+0.4))×10^(-3),pointing toward(l,b)=(334.5°_(-21.6°)^(+25.7°),16.0°_(-16.8°)^(+27.1°)),which is approximately 65°away from the CMB dipole.This implies that the full Pantheon+sample is consistent with a large-scale isotropic universe,but the low-redshift anisotropy could not be purely explained by the peculiar motion of the local universe.