WATER AT Z

We have used the IRAM 30m telescope to search for rotational lines of water and molecular oxygen in the very distant galaxy IRAS 10214+4724 at a redshift of 2.286. We report the tentative detection of the 2(11) --> 2(02) para transition of H2O at 752.0 GHz. This would be the firs t time that a thermal rotational line of water is detected. The ortho transitions 1(10) --> 1(01) and 4(14) --> 3(21) at 556.9 and 380.2 GHz are not detected with intensities at most twice that of the detected 752 GHz line. We cannot derive the water abundance since the line is l ikely optically thick. Assuming that the levels are thermalized at 100 K, the surface filling factor of the H2O emitting cores with respect to the total galaxy size of 8 kpc is about 3 10(-3). We have also obse rved three lines of molecular oxygen towards the same source, but dete cted none. Relative to H-2, this implies an abundance ratio [O2]/[H-2] less-than-or-equal-to 3 10(-4).