In this talk I review the recent construction of a new family of classical
BPS solutions of type IIB supergravity describing 3-branes transverse to a
6-dimensional space with topology R2×ALE. They are
characterized by a non-trivial flux of the supergravity 2-forms through the
homology 2-cycles of a generic smooth ALE manifold. These solutions have two
Killing spinors and thus preserve N=2 supersymmetry. They are
expressed in terms of a quasi harmonic function H (the ``warp factor''),
whose properties was studied in detail in the case of the simplest ALE, namely
the Eguchi-Hanson manifold. The equation for H was identified as an instance
of the confluent Heun equation.Comment: Talk given at the Conference "New Trends in Particle Physics",
September 2001, Yalta, Ukrain