A correlation between spin parameter and dark matter halo mass

TL;DR

This study reveals a correlation between dark matter halo mass and spin parameter at high redshifts, showing that more massive halos tend to have lower spin parameters, with the correlation diminishing at later times.

Contribution

It demonstrates that the correlation between halo mass and spin parameter is consistent across different definitions and depends on formation epoch, using high-resolution cosmological simulations.

Findings

At z > 10, spin parameter decreases with increasing halo mass.

The correlation weakens for halos forming at later times.

Results are consistent across different spin parameter definitions.

Abstract

Using a set of high-resolution dark matter only cosmological simulations we found a correlation between the dark matter halo mass M and its spin parameter lambda for objects forming at redshifts z > 10: the spin parameter decreases with increasing mass. However, halos forming at later times do not exhibit such a strong correlation, in agreement with the findings of previous studies. While we presented such a correlation in a previous study using the Bullock et al. (2001) spin parameter defintion we now defer to the classical definition showing that the results are independent of the definition.