CO emission and associated HI absorption from a massive gas reservoir sourronding the z=3 galaxy B3 J2330+3927

We present results of a comprehensive multi-frequency study of the radio galaxy B3 J2330+3927. The 1.9 arcsec wide radio source, consisting of 3 components, is bracketed by 2 objects in our Keck K-band image. Optical and near-IR Keck spectroscopy of these two objects yield z=3.087+/- 0.004. The brightest (K=18.8) object has a standard type II AGN spectrum, and is the most likely location of the AGN, which implies a one-sided jet radio morphology. Deep 113 GHz observations with the IRAM Plateau de Bure Interferometer reveal CO J=4-3 emission, which peaks at the position of the AGN. The CO line is offset by 500 km s-1 from the systemic redshift of the AGN, but corresponds very closely to the velocity shift of an associated HI absorber seen in Ly’¦Á. This strongly suggests that both originate from the same gas reservoir surrounding the AGN host galaxy. Simultaneous 230 GHz interferometer observations find a ~ 3 x lower integrated flux density when compared to single dish 250 GHz observations with MAMBO at the IRAM 30 m telescope. This can be interpreted as spatially resolved thermal dust emission at scales of 0.5 arcsec to 6 arcsec. Finally, we present a tau < 1.3% limit to the HI 21 cm absorption against the radio source, which represents the seventh non-detection out of 8 z>2 radio galaxies observed to date with the WSRT. We present mass estimates for the atomic, neutral, and ionized hydrogen, and for the dust, ranging from M(HI )=2x 107 Msun derived from the associated HI absorber in Lya up to M(H_2)=7x 1010 Msun derived from the CO emission. This indicates that the host galaxy is surrounded by a massive reservoir of gas and dust. The K-band companion objects may be concentrations within this reservoir, which will eventually merge with the central galaxy hosting the AGN.