We study the concentration parameters , their mass dependence and redshift evolution , of dark-matter halos in different dark-energy cosmologies with constant and time-variable equation of state , and compare them with “ standard ” \Lambda CDM and OCDM models .
We find that previously proposed algorithms for predicting halo concentrations can be well adapted to dark-energy models .
When centred on the analytically expected values , halo concentrations show a log-normal distribution with a uniform standard deviation of \sim 0.2 .
The dependence of averaged halo concentrations on mass and redshift permits a simple fit of the form ( 1 + z ) c = c _ { 0 } ( M / M _ { 0 } ) ^ { \alpha } , with \alpha \approx - 0.1 
throughout .
We find that the cluster concentration depends on the dark energy equation of state at the cluster formation redshift z _ { \mathrm { coll } } through the linear growth factor D _ { + } ( z _ { \mathrm { coll } } ) .
As a simple correction accounting for dark-energy cosmologies , we propose scaling c _ { 0 } from \Lambda CDM with the ratio of linear growth factors , c _ { 0 } \rightarrow c _ { 0 } D _ { + } ( z _ { \mathrm { coll } } ) / D _ { + , \Lambda \mathrm { CDM } } ( z _ { % \mathrm { coll } } ) .