The Sombor index is a novel degree based topological index, based on geometrical considerations. For a graph G, the Sombor index is defined as the sum over all edges uv of G of the terms dᵤ² + dᵥ² where du, dv denote the degrees of the end vertices of uv. In this paper, we determine the first two graphs with maximum Sombor and exponential Sombor indices among cacti of a fixed order and fixed number of cycles. We also characterize such extremal cacti for reduced Sombor index, average Sombor index and p-Sombor index, as well as for generalized Sombor index. By this we extend the results by Das 3 and Liu 13.
Alex et al. (Wed,) studied this question.