2025/08/10 by Saeed Tavasoli, Tavasoli, Saeed, Parsa Ghafour +1
Physics and Astronomy · #Astronomy and Astrophysical Research #Astrophysics and Star Formation Studies #Astrophysics of Galaxies (astro-ph.GA) #COSMIC cancer database #Cosmology and Nongalactic Astrophysics (astro-ph.CO) #Density contrast #FOS: Physical sciences #Galaxies: Formation, Evolution, Phenomena #Galaxy #Observational study #Protein filament #Star formation
paper · pdf · doi:10.48550/arxiv.2508.07480
published in arXiv (Cornell University) (Cornell University)
openalex publication_date 2025/08/10 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/06
This study presents the first extended comparison of cosmic filaments identified in SDSS DR10 observations (z < 0.05) and the IllustrisTNG300-1 ΛCDM simulation (z = 0), utilizing the novel GrAviPaSt filament-finder method. The analyses are performed on both macro- and micro-filaments, each characterized by their length, thickness, and contrast in mass density. In addition to total sample comparisons, two subcategories of micro-filaments, GG (linking galaxy groups) and CC (linking galaxy clusters), are introduced to further analyze discrepancies between the ΛCDM model and observation. While ΛCDM produces extended macro-filaments, such structures are largely absent in SDSS, and where present, they exhibit higher densities than their simulated counterparts. Micro-filaments also show notable density discrepancies: at fixed length and thickness, observational filaments are significantly denser than those in the simulation. Employing radial density profiles reveal that micro-filaments in the ΛCDM simulation exhibit higher contrasts in mass density relative to the background compared to their observational counterparts. Notably, CC type micro-filaments displayed enhanced density contrasts over GG types in the simulation, while observational data showed the opposite trend. Furthermore, SDSS galaxies in both GG and CC micro-filaments exhibit lower specific star formation rates (sSFR) and older stellar populations, while TNG300-1 micro-filaments host more actively star-forming galaxies within the intermediate stellar mass range. These results reveal persistent discrepancies between observational data and the ΛCDM reconstruction of cosmic filaments, pointing to possible tensions in our current understanding of large-scale structures and their environmental effects on galaxy evolution.