2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/75360We study the geometric and algebraic properties of the twisted Poisson structures on Lie algebroids, leading to a definition of their modular class and to an explicit determination of a representative of the modular class, in particular in the case of a twisted Poisson manifold.one reference added, new Section 6.4, orientability assumption deleted, misprints correctedSymplectic GeometryMathematical Physics17B99,53D17,17B62,22E99text