  We give a characterization of geometric property (T) for a coarse disjoint
union of finite graphs with bounded degree using the idea of noncommutative
real algebraic geometry. In the proof, we define a $*$-subalgebra $I_u[X]$ of
real algebraic Roe algebra $\mathbb{R}_u[X]$ over a graph $X$ with bounded
degree. Then we show that $I_u[X]$ contains the Laplacian $\Delta$ as an order
unit with respect to the positive cone ${\sum \limits}^2I_u[X]$ which consists
of sums of hermitian squares.
