On some properties of comma categories

Let $\textup{\bf A}\stackrel{U}{\longrightarrow}\textup{\bf X}$ be an adjoint functor. We show the necessary and sufficient conditions for the comma category $id_{\textup{\bf X}}\downarrow U$ to be algebraic (coalgebraic) and monadic as well as consider factorization structures on $id_{\textup{\bf X}}\downarrow U$.