An anti-correlation between barycentre offsets and velocity dispersion for highest overdensity subhalos in cosmological simulations

Ming-Hua Li; Hai-Nan Lin

doi:10.1093/mnras/sty1731

paper

An anti-correlation between barycentre offsets and velocity dispersion for highest overdensity subhalos in cosmological simulations

arXiv:1808.02647 · doi:10.1093/mnras/sty1731

Abstract

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 halos with large rescaled offsets, i.e. $r_{off} / r_{200} ≳ 0.05$ . The halos which are less massive and at higher redshifts are more likely to have larger $r_{off} / r_{200}$ . The 3D velocity dispersion of the subhalos with largest overdensity is found to have a similar mass and redshift dependence as $r_{off} / r_{200}$ . We also find that the gas subhalos with maximum overdensity and larger gas velocity dispersion $σ_{v}^{ICM, sub} / σ_{200}$ tend to have smaller barycentre offsets $r_{off} / r_{200}$ . Similar result is found for the highest overdensity dark matter subhalos but with less significance. This anti-correlation is more significant for the snapshot $z = 0$ than $z = 0.2$ and $0.5$ . The underlying physical mechanism for this anti-correlation remains to be explored.

arXiv comment11 pages, 12 figures, accepted by MNRAS

An anti-correlation between barycentre offsets and velocity dispersion for highest overdensity subhalos in cosmological simulations

Abstract

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