The first two maximum Sombor spectral radii of bicyclic graphs

The Sombor matrix S ( G ) of a graph G was introduced by Gutman in 2021, in which the ( i, j )-entry is equal to √(deg 2 ( u i ) + deg 2 ( u j )) if the vertices u i and u j are adjacent in G , and zero otherwise, where deg( u i ) denotes the degree of vertex u i in G . In this paper, we obtain the extremal graphs with the first two maximum Sombor spectral radii in bicyclic graphs.