Galaxies falling into a huge galaxy group. Upon entering the group, these galaxies show a blueshift in contrast to the central galaxy. Credit: Dr. Shihong LiaoA study using Sloan Digital Sky Survey information reveals that deep space may be more youthful than approximated, challenging conventional cosmological designs by analyzing satellite galaxy motions around huge groups.In basic cosmological models, the development of cosmological structures begins with the emergence of small structures, which subsequently undergo hierarchical combining, leading to the development of larger systems. As the Universe ages, huge galaxy groups and clusters, being the largest systems, tend to increase in mass and reach a more dynamically relaxed state.The movements of satellite galaxies around these groups and clusters offer valuable insights into their assembly status. The observations of such movement deal important clues about the age of the Universe.By utilizing public information from the Sloan Digital Sky Survey (SDSS), a research study team led by Prof. Qi Guo from the National Astronomical Observatories of the Chinese Academy of Sciences (NAOC) evaluated the kinematics of satellite pairs around huge galaxy groups. The teams findings recommend that deep space might be younger than anticipated by the LCDM design with Planck cosmological parameters.This research study was published in Nature Astronomy on January 22. The accumulative portion of correlated sets as a function of tolerance angle. Credit: Dr. Qing GuThe researchers investigated the motion of satellite pairs positioned on the opposite side of massive galaxy groups by utilizing their velocity offsets from the main galaxy along the line of sight. They discovered a noteworthy excess of pairs showing correlated speed offsets compared to pairs displaying anti-correlated velocity offsets.” The excess of correlated satellite sets suggests the presence of recently accreted or infalling satellite galaxies,” said Prof. Qi Guo, the corresponding author of the paper.This excess was also discovered in updated cosmological simulations but the magnitude of this effect was substantially lower than in observations. The substantial inconsistency between the observations and simulations implies that massive galaxy groups are more youthful in the real Universe.” Since the age of the enormous galaxy groups might be carefully associated to the age of the Universe, these findings consequently recommend a younger Universe compared to that derived from the cosmic microwave background (CMB) by the Planck Collaboration,” said Dr. Qing Gu, very first author of the paper.These findings provide an obstacle to the current cosmological model and may supply important insights into the Hubble tension problem.Reference: “A more youthful Universe implied by satellite pair correlations from SDSS observations of massive galaxy groups” by Qing Gu, Qi Guo, Marius Cautun, Shi Shao, Wenxiang Pei, Wenting Wang, Liang Gao and Jie Wang, 22 January 2024, Nature Astronomy.DOI: 10.1038/ s41550-023-02192-6.
