  We construct a holographic dual to the three-dimensional ABJM Chern-Simons
matter theory with unquenched massive flavors. The flavor degrees of freedom
are introduced by means of D6-branes extended along the gauge theory directions
and delocalized in the internal space. To find the solution we have to solve
the supergravity equations of motion with the source terms introduced by the
D6-branes. The background we get is a running solution representing the
renormalization group flow between two fixed points, at the IR and the UV, in
both of which the geometry is of the form AdS_4 x M_6, where M_6 is a
six-dimensional compact manifold. Along the flow, N=1 supersymmetry is
preserved and the flavor group is Abelian. The flow is generated by changing
the quark mass m_q. When m_q is very large we recover the original unflavored
ABJM solution, while for m_q very small our solution becomes asymptotically
equivalent to the one found recently for massless smeared flavors. We study the
effects of the dynamical quarks as their mass is varied on different
observables, such as the holographic entanglement entropy, the quark-antiquark
potential, the two-point functions of high dimension bulk operators, and the
mass spectrum of mesons.
