The ATLAS liquid argon calorimeters. Commissioning and performances from selected test beams

We present here few results concerning the ATLAS liquid argon calorimeters (LArg). We remind the physics performances of this device obtained in earlier test beam periods and we concentrate in the long commissioning period and the readiness of the detector. Finally, we show results using cosmic muons and from analysis of the first splash and beam halo events recorded during first days of LHC start-up.