Revisiting cosmic anisotropy with the Pantheon+ compilation
- 1China Agricultural University
- 2Yangzhou University
Abstract
We investigate cosmic anisotropy within the updated Pantheon+ sample using both the dipole fitting (DF) and hemisphere comparison (HC) methods. With the DF method, the dipole signal within the full sample is statistically weak. However, the low- z subsample yields a dipole signal of AD = 0.952+0.454−0.403 × 10−3 A D = 0 . 952 - 0.403 + 0.454 × 10 - 3 at ∼ 2σ ∼ 2 σ significance, pointing towards (l,b) = (149.77∘ , −12.20∘ ) ( l , b ) = ( 149 . 77 ∘ , - 12 . 20 ∘ ) . This signal is predominantly driven by a combined subset of surveys 5, 56, 63, and 150, which is characterized by an amplitude of AD = 1.730−0.715+0.554 × 10−3 A D = 1 . 730 - 0.715 + 0.554 × 10 - 3 towards (l,b) = (153.05∘ , −1.25∘ ) ( l , b ) = ( 153 . 05 ∘ , - 1 . 25 ∘ ) . For the HC method, the full sample yields a maximum anisotropy level of ALmax = 0.289 ± 0.052 AL max = 0.289 ± 0.052 oriented towards (l,b) = (127.97∘ , 17.90∘ ) ( l , b ) = ( 127 . 97 ∘ , 17 . 90 ∘ ) with a 1.56σ 1.56 σ significance. This preferred direction is primarily determined by the highly inhomogeneous SNLS subsample, whereas the low- z and high- z subsamples act to suppress the anisotropy level along this axis. These subsample-dependent results suggest that the apparent anisotropy arises from local structures or the inhomogeneous distribution of the datasets rather than an intrinsic cosmic anisotropy.
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BibTeX
@article{zhou2026revisiting,
title = {{Revisiting cosmic anisotropy with the Pantheon+ compilation}},
author = {Yong Zhou and Dong Zhao},
journal = {The European Physical Journal C},
year = {2026},
month = oct,
doi = {10.1140/epjc/s10052-026-16465-7},
url = {https://link.springer.com/article/10.1140/epjc/s10052-026-16465-7},
note = {CC BY 4.0},
}
RIS
TY - JOUR
TI - Revisiting cosmic anisotropy with the Pantheon+ compilation
AU - Yong Zhou
AU - Dong Zhao
PY - 2026
DA - 2026/10/19
JO - The European Physical Journal C
DO - 10.1140/epjc/s10052-026-16465-7
UR - https://link.springer.com/article/10.1140/epjc/s10052-026-16465-7
AB - We investigate cosmic anisotropy within the updated Pantheon+ sample using both the dipole fitting (DF) and hemisphere comparison (HC) methods. With the DF method, the dipole signal within the full sample is statistically weak. However, the low- z subsample yields a dipole signal of A_D = 0.952^+0.454_−0.403 × 10^−3 A D = 0 . 952 - 0.403 + 0.454 × 10 - 3 at ∼ 2σ ∼ 2 σ significance, pointing towards (l,b) = (149.77^∘ , −12.20^∘ ) ( l , b ) = ( 149 . 77 ∘ , - 12 . 20 ∘ ) . This signal is predominantly driven by a combined subset of surveys 5, 56, 63, and 150, which is characterized by an amplitude of A_D = 1.730_−0.715^+0.554 × 10^−3 A D = 1 . 730 - 0.715 + 0.554 × 10 - 3 towards (l,b) = (153.05^∘ , −1.25^∘ ) ( l , b ) = ( 153 . 05 ∘ , - 1 . 25 ∘ ) . For the HC method, the full sample yields a maximum anisotropy level of AL_max = 0.289 ± 0.052 AL max = 0.289 ± 0.052 oriented towards (l,b) = (127.97^∘ , 17.90^∘ ) ( l , b ) = ( 127 . 97 ∘ , 17 . 90 ∘ ) with a 1.56σ 1.56 σ significance. This preferred direction is primarily determined by the highly inhomogeneous SNLS subsample, whereas the low- z and high- z subsamples act to suppress the anisotropy level along this axis. These subsample-dependent results suggest that the apparent anisotropy arises from local structures or the inhomogeneous distribution of the datasets rather than an intrinsic cosmic anisotropy.
SN - 1434-6044
SN - 1434-6052
ER -