  We revisit the 4D generalized black hole geometries, obtained by us [1], with
a renewed interest, to unfold some aspects of effective gravity in a
noncommutative D3-brane formalism. In particular, we argue for the existence of
extra dimensions in the gravity decoupling limit in the theory. We show that
the theory is rather described by an ordinary geometry and is governed by an
effective string theory in 5D. The extremal black hole geometry $AdS_5$
obtained in effective string theory is shown to be in precise agreement with
the gravity dual proposed for D3-brane in a constant magnetic field.
Kaluza-Klein compactification is performed to obtain the corresponding charged
black hole geometries in 4D. Interestingly, they are shown to be governed by
the extremal black hole geometries known in string theory. The attractor
mechanism is exploited in effective string theory underlying a noncommutative
D3-brane and the macroscopic entropy of a charged black hole is computed. We
show that the generalized black hole geometries in a noncommutative D3-brane
theory are precisely identical to the extremal black holes known in 4D
effective string theory.
