The giant Ly alpha nebula associated with a z=2.5 radio galaxy

We present a kinematic and morphological study of the giant Ly alpha nebula associated with the radio galaxy MRC 2104-242 (z = 2.49) based on integral field spectroscopic VIMOS data from VLT. The galaxy appears to be embedded in a giant (greater than or similar to 120 kpc) gas reservoir that surrounds it completely. The kinematic properties of the nebula suggest that it is a rotating structure, which would imply a lower limit to the dynamical mass of similar to 3 x 10(11) M circle dot. An alternate scenario is that the gas is infalling. Such a process would be able to initiate and sustain significant central starburst activity, although it is likely to contribute with less than 10% of the total stellar mass of the galaxy.