Rapidity dependence of HBT correlation radii in non-boost invariant models

Hanbury-Brown Twiss (HBT) correlation measurements provide valuable information about the phase space distribution of matter in ultrarelativistic heavy-ion collisions. The rapidity dependence of HBT radii arises from a nontrivial interplay between longitudinal and transverse expansion and the time dependence of the freeze-out pattern. For a non-accelerating longitudinal expansion the dependence primarily arises from the amount of radiating matter per unit rapidity $dN/d\eta$, but for a scenario with strong longitudinal acceleration additional complications occur. In this paper I explore schematically what type of dependence can be expected for RHIC conditions under different model assumptions for the dynamics of spacetime expansion and freeze-out.