A characterisation of Thas maximal arcs in translation planes of square order (Q1339783)

In 1974 J. A. Thas constructed a class of maximal \(\{q^ 3 - q^ 2 + q;q\}\)-arcs in certain translation planes of order \(q^ 2\), starting from a spread in \(\text{PG}(3,q)\) and an ovoid in \(PG(4,q)\). The authors characterize this class as maximal arcs belonging to a translation plane of order \(q^ 2\) and stabilised by a homology of order \(q - 1\). Moreover they give a characterization involving Baer sublines in the Desarguesian case.