Orthogonal graphs over Galois rings of odd characteristic

Assume that ν is a positive integer and δ=0,1 or 2. In this paper we introduce the orthogonal graph Γ2ν+δ over a Galois ring of odd characteristic and prove that it is arc transitive. Moreover, we compute its parameters as a quasi-strongly regular graph. In particular, we show that Γ2+δ is a strongly regular graph and Γ2ν+1 is a strictly Deza graph when ν≥2.