We employ the hemisphere comparison ( HC ) method and the dipole fitting ( DF ) method to investigate the cosmic anisotropy in the recently released Pantheon sample of type Ia supernovae ( SNe Ia ) and five combinations among Pantheon .
For the HC method , we find the maximum anisotropy level in the full Pantheon sample is \mathrm { AL } _ { max } = 0.361 \pm 0.070 and corresponding direction ( l,b ) = ( { 123.05 ^ { \circ } } ^ { +11.25 ^ { \circ } } _ { -4.22 ^ { \circ } } , { 4.78 ^ { \circ } } ^ { +1.80 % ^ { \circ } } _ { -8.36 ^ { \circ } } ) .
A robust check shows the statistical significance of maximum anisotropy level is about 2.1 \sigma .
We also find that the Low- z and SNLS subsamples have decisive impact on the overall anisotropy while other three subsamples have little impact .
Moreover , the anisotropy level map significantly rely on the inhomogeneous distribution of SNe Ia in the sky .
For the DF method , we find the dipole anisotropy in the Pantheon sample is very weak .
The dipole magnitude is constrained to be less than 1.16 \times 10 ^ { -3 } at 95 \% confidence level .
However , the dipole direction is well inferred by MCMC method and it points towards ( l,b ) = ( { 306.00 ^ { \circ } } ^ { +82.95 ^ { \circ } } _ { -125.01 ^ { \circ } } , { -34.20 ^ { \circ } } ^ { + % 16.82 ^ { \circ } } _ { -54.93 ^ { \circ } } ) .
This direction is very close to the axial direction to the plane of SDSS subsample .
It may imply that SDSS subsample is the decisive part to the dipole anisotropy in the full Pantheon sample .
All these facts imply that the cosmic anisotropy found in Pantheon sample significantly rely on the inhomogeneous distribution of SNe Ia in the sky .
More homogeneous distribution of SNe Ia is necessary to search for a more convincing cosmic anisotropy .