The spatial distribution deviation and the power suppression of baryons from dark matter

Abstract

The spatial distribution between dark matter and baryonic matter of the Universe is biased or deviates from each other. In this work, by comparing the results derived from IllustrisTNG and WIGEON simulations, we find that many results obtained from TNG are similar to those from WIGEON data, but differences between the two simulations do exist. For the ratio of density power spectrum between dark matter and baryonic matter, as scales become smaller and smaller, the power spectra for baryons are increasingly suppressed for WIGEON simulations; while for TNG simulations, the suppression stops at k = 15 − 20 hMpc −1 , and the power spectrum ratios increase when k > 20 hMpc −1 . The suppression of power ratio for WIGEON is also redshift-dependent. From z = 1 to z = 0, the power ratio decreases from about 70% to less than 50% at k = 8 hMpc −1 . For TNG simulation, the suppression of power ratio is enhanced with decreasing redshifts in the scale range k > 4 hMpc −1 , but is nearly unchanged with redshifts in k < 4 hMpc −1 . These results indicate that turbulent heating can also have the consequence to suppress the power ratio between baryons and dark matter. Regarding the power suppression for TNG simulations as the norm, the power suppression by turbulence for WIGEON simulations is roughly estimated to be 45% at k = 2 hMpc −1 , and gradually increases to 69% at k = 8 hMpc −1 , indicating the impact of turbulence on the cosmic baryons are more significant on small scales.