Searches for supersymmetry in events with photons or tau leptons and missing transverse momentum with the ATLAS detector

Models with gauge-mediated supersymmetry breaking predict that the lightest supersymmetric particle is a gravitino with negligible mass so that the phenomenology of the supersymmetric events produced at the LHC is determined by the next-to-lightest supersymmetric particle (NLSP). Depending on the model parameters, the NLSP can be a neutralino with significant bino admixture that will decay into a photon, or a stau that will decay into a tau lepton. The talk presents results from searches for supersymmetry in events with photons or taus and missing transverse momentum, using the data sample recorded in 2011 at $\sqrt{s}=7$ TeV centre-of-mass energy by the ATLAS experiment at the LHC.