CO emission and associated H I absorption from a massive gas reservoir surrounding the z = 3 radio galaxy B3 J2330+3927^*

¹ Institut d'Astrophysique de Paris, CNRS, 98bis boulevard Arago, 75014 Paris, France e-mail: [debreuck, omont, rocca]@iap.fr
² Institut de Radioastronomie Millimétrique, 300 rue de la piscine, 38406 St. Martin-d'Hères, France e-mail: neri@iram.fr
³ ASTRON, Postbus 2, 7990 AA Dwingeloo, The Netherlands e-mail: morganti@nfra.nl
⁴ Jet Propulsion Laboratory, California Institute of Technology, Mail Stop 169-327, Pasadena, CA 91109, USA e-mail: stern@zwolfkinder.jpl.nasa.gov
⁵ IGPP/LLNL, L-413, 7000 East Ave, Livermore, CA 94550, USA e-mail: [mreuland, wil]@igpp.ucllnl.org
⁶ Sterrewacht Leiden, Postbus 9513, 2300 RA Leiden, The Netherlands e-mail: rottgeri@strw.leidenuniv.nl
⁷ Department of Physics, University of California, Davis, CA 95616, USA e-mail: adam@igpp.ucllnl.org
⁸ Department of Astronomy, University of California, Berkeley, CA 94720, USA e-mail: spinrad@astro.berkeley.edu
⁹ Istituto di Radioastronomia del CNR, Via Gobetti 101, 40129 Bologna, Italy e-mail: vigotti@ira.bo.cnr.it
¹⁰ Radio Astronomy Laboratory, University of California, Berkeley, CA 94720, USA e-mail: mwright@astro.berkeley.edu

Corresponding author: C. De Breuck, debreuck@iap.fr

Received: 12 August 2002
Accepted: 7 February 2003

Abstract

We present results of a comprehensive multi-frequency study of the radio galaxy B3 J2330+3927. The 19 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 . The brightest () 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  emission, which peaks at the position of the AGN. The CO line is offset by 500 from the systemic redshift of the AGN, but corresponds very closely to the velocity shift of an associated  absorber seen in Lyα. This strongly suggests that both originate from the same gas reservoir surrounding the AGN host galaxy. Simultaneous 230 GHz interferometer observations find a ~ 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 05 to 6´´. Finally, we present a % limit to the  21 cm absorption against the radio source, which represents the seventh non-detection out of 8 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   derived from the associated  absorber in Lyα up to   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.