A recurrence relation $a_n = c_1 a_{n-1} + c_2 a_{n-2}$ has the characteristic roots $r_1 = 1 + i$ and $r_2 = 1 - i$. Express the roots in polar form $r = \rho(\cos \theta + i \sin \theta)$. What are $\rho$ and $\theta$?