Implementation and Performance of the High-Level Trigger electron and photon selection for the ATLAS experiment at the LHC

The ATLAS three-tier trigger system faces the challenge to reduce the incoming rate of 40 MHz to ∼ 200 Hz. It consists of hardware based Level-1, and a software based High-Level Trigger (HLT). In this talk an overview of the selection algorithms for electrons and photons will be given as well as the expected performance. The electron and photon trigger menu and the strategy for the initial phase of LHC exploitation.