Automorphisms of two-dimensional RAAGs and partially symmetric   automorphisms of free groups
  We compute the virtual cohomological dimension (VCD) of the group of partially symmetric outer automorphisms of a free group. We use this to obtain new upper and lower bounds on the VCD of the outer automorphism group of a two-dimensional right-angled Artin group. In the case of a right-angled group with defining graph a tree, the bounds agree. 
Kai-Uwe Bux, Ruth Charney and Karen Vogtmann