Spectral radius and rainbow $k$-factors of graphs

Let $\mathcal{G}=\{G_1,\dots ,G_{\frac{kn}{2}}\}$ be a set of graphs on the same vertex set $V=\{1,\dots ,n\}$ where $k\cdot n$ is even. We say $\mathcal{G}$ admits a rainbow $k$-factor if there exists a $k$-regular graph $F$ on the vertex set $V$ such that all edges of $F$ are from different members of $\mathcal{G}$. In this paper, we show a sufficient spectral condition for the existence of a rainbow $k$-factor for $k\ge 2$, which is that if $\rho (G_i)\ge \rho (K_{k-1}\vee (K_1\cup K_{n-k}))$ for each $G_i\in \mathcal{G}$, then $\mathcal{G}$ admits a rainbow $k$-factor unless $G_1=G_2=\cdots =G_{\frac{kn}{2}}\cong K_{k-1}\vee (K_1\cup K_{n-k})$.