Probing the cosmological principle with the CSST photometric survey

Abstract

The cosmological principle states that our Universe is statistically homogeneous and isotropic at large scales. However, due to the relative motion of the Solar System, an additional kinematic dipole can be detected in the distribution of galaxies, which should be consistent with the dipole observed in the cosmic microwave background (CMB) temperature. In this paper, we forecast the mock number count maps from the China Space Station Telescope photometric survey to reconstruct the kinematic dipole. Using the whole photometric mock data, we obtain a positive evidence for the dipole signal detection at 3σ confidence level, and the significance would be increased to 4σ when we only use the high-redshift samples with z = 1.8 ∼ 4. This result can provide a good consistency check between the kinematic dipoles measured in the CMB and that from the large scale structure, which can help us to verify the basic cosmological principle.