科研之友
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摘要
In this paper, we use two hydrodynamic simulations to study the barycentre offsets r(off) between the entire halo and the gas or dark matter subhalo with largest overdensity. We restrict our analysis to those haloes with large rescaled offsets, i.e. r(off)/r(200) >= 0.05. The haloes which are less massive and at higher redshifts are more likely to have larger r(off)/r(200). The 3D velocity dispersion of the subhaloes with largest overdensity is found to have a similar mass and redshift dependence as r(off)/r(200). We also find that the gas subhaloes with maximum overdensity and larger gas velocity dispersion sigma(ICM,sub)(nu)/sigma(200) tend to have smaller barycentre offsets r(off)/r(200). Similar result is found for the highest overdensity dark matter subhaloes but with less significance. This anticorrelation is more significant for the snapshot z = 0 than z = 0.2 and 0.5. The underlying physical mechanism for this anticorrelation remains to be explored.
