Subconstituents of orthogonal graphs of odd characteristic - continued

The subconstituents of the orthogonal graph O(2ν+δ,q), where ν⩾2 and δ∈{1,2}, over a finite field of odd characteristic are shown to be quasi-strongly regular. Furthermore, the first subconstituent is shown to be co-edge regular, and when ν⩾3 its automorphism group is determined. The second subconstituent is shown to be edge regular, and when ν⩾2 its automorphism group is determined. Their parameters and chromatic numbers are also determined.