((F, D1), D3) Bound State and Its T-dual Daughters

In the previous paper [hep-th/9904129], we constructed a general explicit BPS solution for (F, D3) non-threshold bound state. By using the SL(2,Z) symmetry of type IIB string theory, we here construct from (F, D3) a more general BPS configuration for a D3 brane with certain units of quantized 5-form flux and an infinite number of parallel (F, D1)-strings. We study its decoupling limit and find that given Maldacena's $AdS_5/CFT_4$ correspondence with respect to simple D3 branes and with the usual string coupling, we should have a similar correspondence with respect to this bound state but now with an effective string coupling. We discuss possible descendants of this bound state by T-dualities along its longitudinal or transverse directions. In particular, we present explicit configurations for ((F, Dp), D(p + 2)) bound states for $2 \le p \le 5$. All these configurations preserve one half of the spacetime supersymmetries.