Comments on the distinction between color- and flavor-branes and new D3-D7 solutions with eight supercharges

Abstract: We investigate the distinction between color- and flavor-branes, that is usually made in the context of gauge/string duality with backreacting flavors. Our remarks are based on a series of examples concerning the role of source terms in relatively simple supergravity backgrounds that allow for a well-controlled approach to the problem. The observations suggest that, in opposite to general practice, one could consider such terms for both kinds of branes, while their presence is only essential for smeared sources - as is commonly the case for flavor-branes. Among the examples studied are D3-D7 systems with eight supercharges, where the D7-branes are assumed to be smeared. Starting from a fairly generic ansatz, we will find new analytic and numeric solutions and briefly compare these to previous work in this field.