ATLAS Trigger Menus for the LHC Start-Up Phase

This note gives an overview of the ATLAS physics selection strategy for the initial running period of LHC and an assumed maximum luminosity of 2$\cdot {\rm 10^{33} cm^{-2}s^{-1}}$. We present various contributions to the trigger menu, ranging from inclusive physics triggers over prescaled physics and monitoring triggers to pure calibration and monitoring triggers. We also try to give motivations for the various choices of trigger items where appropriate and useful. Finally, we study the effect of our trigger information compilation on the required abilities and capacities of the LVL1 trigger, and specifically on the number of required trigger items of the LVL1 central trigger processor.