We report a sensitive search for redshifted CO ( 3–2 ) emission from the weak radio galaxy 53W002 at z=2.394 .
Maps at resolutions of 3 \arcsec and 235 km s ^ { -1 } show a significant emission peak within 0.5 \arcsec of the optical and radio continuum peaks .
The measured narrow band flux is approximately ten times the extrapolated cm-wavelength non-thermal radio continuum expected at 101.9 GHz and exhibits a spectral profile implying a 540 km s ^ { -1 } width ( FWHM ) at a systemic redshift z = 2.394 \pm 0.001 for CO ( 3-2 ) .
This emission has a total integrated flux of 1.51 \pm 0.2 Jy km s ^ { -1 } , approximately 4 times weaker than that previously seen in the lensed systems FSC10214+4724 and the Cloverleaf QSO .
For a Galactic CO-to-H _ { 2 } conversion ratio , the implied molecular gas mass is 7.4 \times 10 ^ { 10 } M _ { \odot } ( H _ { 0 } =75 km s ^ { -1 } Mpc ^ { -1 } and q _ { 0 } =0.5 ) .
The CO emission is elongated at PA = 120 ^ { \circ } with a deconvolved major axis radius of 15 kpc ( 2.8 \arcsec ) .
This extension is along a similar direction to that seen in the cm-wave radio continuum and the optical but approximately three times larger .
A velocity gradient is seen along the major axis , and if this structure is a ( forming ) disk , the implied dynamical mass is 9-22 \times 10 ^ { 10 } M _ { \odot } at r \leq 15 kpc , assuming inclination i = 0 ^ { \circ } ( edge-on ) .
The magnitude of these masses and the similarity of the high gas-mass fraction are consistent with the host galaxy of 53W002 being a young galactic system but the metallicity ( probably \geq 0.1 Z _ { \odot } in order to produce the CO lines ) implies significant heavy element production prior to z=2.4 .
This constitutes the first high redshift molecular gas which is detected in emission where there is probably no gravitational magnification .