The large-scale galaxy redshift survey is a powerful tool for exploring the universe. Scientists can obtain the distribution of galaxy positions in space by measuring the spectra of a large number of distant celestial bodies, which contains rich information on galaxy clustering. Researchers further use statistical methods to analyze data to reveal the large-scale structure of the universe, which is crucial for studying the properties of dark energy.
With the evolution of the universe, the detected large-scale structure of the universe has undergone nonlinear evolution, resulting in the leakage of cosmological information towards higher-order statistics. Meanwhile, obtaining information on the clustering of these galaxies requires analysis beyond two statistical points. Due to the complexity of high-order statistics, the measurement and modeling of multi-point statistics pose certain challenges.
The National Astronomical Observatory of the Chinese Academy of Sciences and its international counterparts, based on the reconstruction technology of galaxy density field, proposed a method to jointly analyze the pre reconstruction and post reconstruction galaxy density field, and found that most high-order information can be effectively extracted from two-point statistics, which has taken a key step in obtaining cosmological information in galaxy surveys.
In order to achieve the application of the new method's measured data, the team conducted a series of modeling studies. This study utilized high-precision numerical simulation to develop simulator modeling techniques, and established high-precision simulators for the cross power spectra of the power spectrum before and after reconstruction, as well as the density field before and after reconstruction. The predicted power spectrum accuracy was between 1-10%. Research on simulator based cosmological analysis has found that the precision of cosmological parameters such as cosmic material density and Hubble constant has been improved. This achievement lays the foundation for the analysis of measured data.
Recently, the relevant research results were published online in the Journal of Astrophysics. The research work was supported by the National Natural Science Foundation of China, the National Key R&D Program and the Chinese Academy of Sciences Youth Team Program for Stable Support in Basic Research.
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