For a graph G=(V,E) and viββV, denote by dviββ (or diβ for
short) the degree of vertex viβ. The p-Sombor matrix
Spβ(G) (pξ =0) of a graph G is a square matrix,
where the (i,j)-entry is equal to (dipβ+djpβ)p1β if the vertices viβ and vjβ are
adjacent, and 0 otherwise. The p-Sombor spectral radius of G, denoted by
Ο(Spβ(G)), is the largest eigenvalue of
the p-Sombor matrix Spβ(G). In this paper, we consider
the extremal trees, unicyclic and bicyclic graphs with respect to the
p-Sombor spectral radii. We characterize completely the extremal graphs with
the first three maximum Sombor spectral radii, which answers partially a
problem posed by Liu et al. in [MATCH Commun. Math. Comput. Chem. 87 (2022)
59-87]