A study using data from the Sloan Digital Sky Survey reveals that the Universe may be younger than estimated, and by analyzing the motion of satellite galaxies around large populations challenging the theoretical model.
In standard cosmological models, the formation of cosmological structures begins with the appearance of small structures, followed by hierarchical fusion, leading to the formation of larger systems. As the Universe ages, the largest systems, large galaxy groups and clusters, tend to increase in mass and reach a more dynamically relaxed state.
The movement of satellite galaxies around these groups and clusters provides valuable insight into their collective state. Observations of such motion provide important clues about the age of the universe.
A research team led by Professor Qi Guo from the National Astronomical Observatory of the Chinese Academy of Sciences (NAOC) used public data from the Sloan Digital Sky Survey (SDSS) to analyze the kinematics of satellite pairs around a large group of galaxies. The researchers’ findings suggest that the universe may be younger than predicted by LCDM models using Planck cosmology parameters.
This research natural astronomy January 22nd.
The researchers used velocity offsets from the central galaxy along the line of sight to investigate the motion of pairs of satellites located on opposite sides of a massive galaxy group. They found a significant excess of pairs exhibiting correlated velocity offsets compared to pairs exhibiting anticorrelated velocity offsets.
“The excess of correlated satellite pairs suggests the presence of recently accreted or fallen satellite galaxies,” said Professor Qi Guo, corresponding author of the paper.
This excess was also found in modern cosmological simulations, but the magnitude of this effect was much smaller than observations. The large discrepancy between observations and simulations means that large groups of galaxies are younger in the real universe.
“Since the ages of large groups of galaxies may be closely related to the age of the universe, these discoveries are a result of the Cosmic Microwave Background Radiation (CMB) obtained from the Planck Collaboration. “This suggests a younger universe compared to the previous year,” said Dr. Qing Gu. , first author of the paper.
These discoveries present a challenge to current cosmological models and may provide valuable insight into the Hubble tension problem.
Reference: “Satellite pair correlations from SDSS observations of giant galaxy groups suggest a young universe” Qing Gu, Qi Guo, Marius Cautun, Shi Shao, Wenxiang Pei, Wenting Wang, Liang Gao, Jie Wang, January 22, 2024 Day, natural astronomy.
DOI: 10.1038/s41550-023-02192-6