The second detection of CO at redshift larger than 4

S. Guilloteau , A. Omont , R.G. McMahon , P. Cox , P. Petitjean
Institut de RadioAstronomie Millimétrique, 300 rue de la Piscine, F-38406 Saint Martin d'Hères, France
Institut d'Astrophysique de Paris, CNRS, 98bis Bd Arago, F-75014 Paris
Institute of Astronomy, Madingley Road, Cambridge CB3 0HA, U.K.
Institut d'Astrophysique Spatiale, Université Paris 11, F-91406 Orsay Cedex
Abstract: We report the detection with the IRAM interferometer at 3mm of J=5-4 CO line in the radio quiet quasar BRI 1335-0415 at redshift of z=4.41 (Fig. 7). After BR 1202-0725 at z=4.69 (Ohta 1996, Omont 1996a), this is the second detection of CO at z>3. The integrated line intensity is  Jy km s with a linewidth of 420 60 km s . The dust continuum emission has also been mapped at 1.35 mm (Fig. 6). The 1.35 mm flux is found to be 5.6 1.1 mJy. The ratio of the CO to 1.35mm continuum flux is slightly larger than for BR 1202-0725. Contrary to the case of BR 1202-0725, there is only marginal evidence of extension of the 1.35 mm continuum and 3mm CO emission. In the absence of gravitational lensing, for which there is no a priori evidence, and within the uncertainties of the CO to M(H ) conversion factors, the mass of molecular gas M(H ) could be M .

  
Figure: 1.35 mm continuum map of BRI 1335-0415. Contour step is 1 mJy/beam, and the rms noise 0.7 mJy/beam. The cross indicates the optical position.

  
Figure: Spectrum of the CO J=5-4 line towards BRI 1335-0415, superimposed with the best Gaussian profile. Errorbars are . The velocity scale corresponds to a frequency of 106.570 GHz corresponding to a redshift .