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Abstract: We consider solutions of (super) gravities associated to non-critical (super) string theories in arbitrary space–time dimension , that describe generically non-extremal black p-branes charged under NSNS or RR gauge fields, embedded in some non-critical vacuum. In the case of vacuum (uncharged) backgrounds, we solve completely the problem obtaining all the possible solutions, that consist of the -dimensional Minkowski space–times a linear dilaton times an , and a three parameter family of solutions that includes -dimensional Minkowski space–times the cigar, and its T-dual -dimensional Minkowski space–times the trumpet. For NSNS charged solutions, we also solve in closed form the problem, obtaining several families of solutions, that include in particular the fundamental non-critical string solution embedded in the cigar vacuum, recently found in [A.R. Lugo, M.B. Sturla, Phys. Lett. B 637 (2006) 338, hep-th/0604202], a solution that we interpret as a fundamental non-critical string embedded in the linear dilaton vacuum, and a two-parameter family of regular curvature solutions asymptotic to . In the case of RR charged Dp-branes solutions, an ansatz allows us to find a non-conformal, constant curvature, asymptotically space, T-dual to , together with a two-parameter family of solutions that includes the non-conformal, AdS black hole like solution associated with the earlier space. The solutions obtained by T-duality are Einstein spaces consisting of a two-parameter family of conformal, constant dilaton solutions, that include, in particular, the AdS black hole of [S. Kuperstein, J. Sonnenschein, JHEP 0407 (2004) 049, hep-th/0403254]. We speculate about the possible applications of some of them in the framework of the gauge-gravity correspondence. [Copyright &y& Elsevier]

Abstract: We study a system of coincident D4- and -branes with non-zero world-volume magnetic fields in the weak coupling limit. We show that the conditions for absence of tachyons in the spectrum coincide exactly with those found in [hep-th/0206041], in the low energy effective theory approach, for the system to preserve a of the supersymmetries of the type IIA string theory vacuum. We present further evidence about the stability of the system by computing the lowest order interaction amplitude from both open and closed channels, thus verifying the no force condition as well as the supersymmetric character of the spectrum. A brief discussion of the low energy effective five-dimensional world-volume theory is given. [Copyright &y& Elsevier]

We analyze in the spirit of hep-th/0110039 the possible existence of supersymmetric Dp–Dp brane systems in flat ten-dimensional Minkowski space. For p=3,4 we show that besides the solutions related by T-duality to the D2–D2 systems found by Bak and Karch there exist other ansatz whose compatibility is shown from general arguments and that preserve also eight supercharges, in particular, a D4–D4 system with D2-branes dissolved on it and Taub–NUT charge. We carry out the explicit construction in Weyl basis of the corresponding Killing spinors and conjecture the existence of new solutions for higher-dimensional branes with some compact directions analogous to the supertube recently found. [Copyright &y& Elsevier]