We present a catalogue of 348 galaxy clusters and groups with 0.2 < z < 1.2 selected in the 2.78 deg ^ { 2 } ALHAMBRA Survey .
The high precision of our photometric redshifts , close to 1 \% , and the wide spread of the seven ALHAMBRA pointings ensure that this catalogue has better mass sensitivity and is less affected by cosmic variance than comparable samples .

The detection has been carried out with the Bayesian Cluster Finder ( BCF ) , whose performance has been checked in ALHAMBRA-like light-cone mock catalogues .
Great care has been taken to ensure that the observable properties of the mocks photometry accurately correspond to those of real catalogues .
From our simulations , we expect to detect galaxy clusters and groups with both 70 \% completeness and purity down to dark matter halo masses of M _ { h } \sim 3 \times 10 ^ { 13 } M _ { \odot } for z < 0.85 .
Cluster redshifts are expected to be recovered with \sim 0.6 \% precision for z < 1 .
We also expect to measure cluster masses with \sigma _ { M _ { h } |M ^ { * } _ { CL } } \sim 0.25 - 0.35 dex precision down to \sim 3 \times 10 ^ { 13 } M _ { \odot } , masses which are 50 \% smaller than those reached by similar work .

We have compared these detections with previous optical , spectroscopic and X-rays work , finding an excellent agreement with the rates reported from the simulations .
We have also explored the overall properties of these detections such as the presence of a colour-magnitude relation , the evolution of the photometric blue fraction and the clustering of these sources in the different ALHAMBRA fields .
Despite the small numbers , we observe tentative evidence that , for a fixed stellar mass , the environment is playing a crucial role at lower redshifts ( z < 0.5 ) .