Colloquium on Dec. 26, 2024

Discrepancies in Cosmological Simulations: Uncovering the Black Hole, Star Formation, and Dark Matter Connection in Nearby Galaxies

Speaker: Yassen Yesuf (SHAO)

Venue: SWIFAR Building 2111

Time: 16:00 PM, Thursday, Dec. 26, 2024

Abstract:

Environmental factors and supermassive black hole (SMBH) feedback are critical components of galaxy evolution. I will provide an overview of our comprehensive comparative analysis of observed and simulated galaxies. This analysis examines stellar mass, star formation rate, halo mass, environments, and SMBH properties using multiwavelength data from nearby galaxies in the SDSS and GAMA surveys. I will highlight new measurements and findings, emphasizing major inconsistencies between the properties of approximately 40,000 nearby active galactic nuclei (AGNs: Seyferts and quasars), identified in Sloan data, and those of simulated AGNs in the TNG, EAGLE, and SIMBA cosmological simulations. While both simulations and observations qualitatively indicate a prevalence of strongly accreting SMBHs in gas-rich, star-forming host galaxies within low-density environments, substantial quantitative discrepancies exist. These include differences in the distribution of stellar mass, star formation rates in host galaxies, as well as black hole mass and accretion luminosity functions. Moreover, the simulations fail to accurately reproduce the star formation rates or quenched fractions of galaxies with inactive galaxies across various environments. All simulations overpredict the quenched fraction by more than 30% in low-mass galaxies within high density environments, while they offer differing predictions for galaxies with high stellar mass.