Searches for monojets and monophotons with the ATLAS detector

These slides present the searches for events with a high-$p_{T}$ photon in combination with $E_{T}^{miss}$ using 4.6 fb$^{-1}$ of proton-proton collisions at $sqrt{s} = 7$ TeV and the searches for events with a high-$p_{T}$ jet in combination with $E_{T}^{miss}$ using 4.7 fb$^{-1}$ and 10.5 fb$^{-1}$ of proton-proton collisions at $sqrt{s} = 7$ and $sqrt{s} = 8$ TeV respectively with the ATLAS detector. No significant excess of data over the expectation from the Standard Model has been observed in both final states, and limits are set on the visible cross section of production of new physics signals.