2004A&A...419...99G

We report on the detection of the lowest CO J1-0 transition in the powerful high-redshift radio galaxy 4C60.07 at z=3.79. The CO emission is distributed in two spatially and kinematically distinct components as was previously known from the observations of the higher excitation CO J4-3 line. The total molecular gas mass in 4C60.07 inferred from the CO J1-0 emission is M(H₂)≃1.3x10¹¹M_☉, sufficient to fuel the inferred star-formation rate of ∼1600M_☉/yr for 10⁸yrs. From our high-resolution CO J1-0 VLA maps we find the dynamical mass of 4C60.07 to be comparable to that of a giant elliptical at the present time. A significant fraction of the mass is in the form of molecular gas suggesting that 4C60.07 is in an early state of its evolution. The merging nature of 4C60.07 along with its large dynamical mass imply that this system is a giant elliptical caught in its formative stages.