We investigate the growth histories of dark matter halos associated with dwarf satellites in Local Group galaxies and the resultant evolution of the baryonic component .
Our model is based on the recently proposed property that the mean surface density of a dark halo inside a radius at maximum circular velocity V _ { max } is universal over a large range of V _ { max } .
Following that this surface density of 20 M _ { \odot } pc ^ { -2 } well explains dwarf satellites in the Milky Way and Andromeda , we find that the evolution of the dark halo in this common surface-density scale is characterized by the rapid increase of the halo mass assembled by the redshift z _ { TT } of the tidal truncation by its host halo , at early epochs of z _ { TT } \hskip { 3.0 pt } \raisebox { 1.72 pt } { $ > $ } \hskip { -7.5 pt } \raisebox { -3.01 pt } { % $ \sim$ } \hskip { 3.0 pt } 6 or V _ { max } \hskip { 3.0 pt } \raisebox { 1.72 pt } { $ < $ } \hskip { -7.5 pt } \raisebox { -3.01 pt } % { $ \sim$ } \hskip { 3.0 pt } 22 km s ^ { -1 } .
This mass growth of the halo is slow at lower z _ { TT } or larger V _ { max } .
Taking into account the baryon content in this dark halo evolution , under the influence of the ionizing background radiation , we find that the dwarf satellites are divided into roughly two families : those with V _ { max } \hskip { 3.0 pt } \raisebox { 1.72 pt } { $ < $ } \hskip { -7.5 pt } \raisebox { -3.01 pt } % { $ \sim$ } \hskip { 3.0 pt } 22 km s ^ { -1 } having high star formation efficiency and those with larger V _ { max } having less efficient star formation .
This semi-analytical model is in agreement with the high-resolution numerical simulation for galaxy formation and with the observed star formation histories for Fornax and Leo II .
This suggests that the evolution of a dark halo may play a key role in understanding star formation histories in dwarf satellites .