Context :

Aims : To investigate the impact of radio jets during the formation epoch of their massive host galaxies , we present an analysis of two massive , \log { M _ { stellar } / M _ { \odot } } \sim 10.6 and 11.3 , compact radio galaxies at z = 3.5 , TNJ0205+2242 and TNJ0121+1320 .
Their small radio sizes ( R \leq 10 kpc ) are most likely a sign of youth .
In particular , we compare their radio properties and gas dynamics with those in well extended radio galaxies at high redshift , which show strong evidence for powerful , jet-driven outflows of significant gas masses ( { M } \sim 10 ^ { 9 - 10 } M _ { \odot } ) .

Methods : Our analysis combines rest-frame optical integral-field spectroscopy obtained with SINFONI on the VLT with existing radio imaging , CO ( 4–3 ) emission line spectra , and rest-frame UV longslit spectroscopy .

Results : [ OIII ] \lambda 5007 line emission is compact in both galaxies and lies within the region defined by the radio lobes .
For TNJ0205+2242 , the Ly \alpha profile narrows significantly outside the jet radius , indicating the presence of a quiescent halo .
TNJ0121+1320 has two components at a projected relative distance of \sim 10 kpc and a velocity offset of \sim 300 km s ^ { -1 } , measured from the [ OIII ] \lambda 5007 velocity map .
This suggests that the fainter component is orbiting around the more massive , radio-loud galaxy .
If motions are gravitational , this implies a dynamical mass of 2 \times 10 ^ { 11 } M _ { \odot } for the radio-loud component .

Conclusions : The dynamical mass , molecular gas mass measured from the CO line emission , and radio luminosity of these two compact radio galaxies imply that compact radio sources may well develop large-scale , energetic outflows as observed in extended radio galaxies , with the potential of removing significant fractions of the ISM from the host galaxy .
The absence of luminous emission line gas extending beyond the radio emission in these sources agrees with the observed timescales and outflow rates in extended radio galaxies , and adds further evidence that the energetic , large-scale outflows observed in extended radio sources ( Nesvadba et al .
2006 ) are indeed the result of influence of the radio jet .