Automorphism group of plane curve computed by Galois points, II

Recently, the first author [3] classified finite groups obtained as automorphism groups of smooth plane curves of degree d ≥ 4 into five types. He gave an upper bound of the order of the automorphism group for each types. For one of them, the type (a-ii), that is given by max{2d(d – 2), 60d}. In this article, we shall construct typical examples of smooth plane curve C by applying the method of Galois points, whose automorphism group has order 60d. In fact, we determine the structure of the automorphism group of those curves.