Searches for monojets and monophotons with the ATLAS detector

Searches for new phenomena in events with a high-energy jet or photon and missing transverse momentum in the final state are performed using events from proton-proton collisions at center of mass energy of 7~TeV and 8~TeV with the ATLAS experiment at the LHC. No excess of events beyond expectations from Standard Model processes is observed. New exclusion limits are obtained on the presence of large extra spatial dimensions, the pair production of dark matter candidates, and the associate production of light gravitons and squark/gluinos in a given supersymmetric scenario.