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The second detection of CO at redshift larger than 4

S. Guilloteau tex2html_wrap_inline729 , A. Omont tex2html_wrap_inline731 , R.G. McMahon tex2html_wrap_inline733 , P. Cox tex2html_wrap_inline735 , P. Petitjean tex2html_wrap_inline731
tex2html_wrap_inline729 Institut de RadioAstronomie Millimétrique, 300 rue de la Piscine, F-38406 Saint Martin d'Hères, France
tex2html_wrap_inline731 Institut d'Astrophysique de Paris, CNRS, 98bis Bd Arago, F-75014 Paris
tex2html_wrap_inline733 Institute of Astronomy, Madingley Road, Cambridge CB3 0HA, U.K.
tex2html_wrap_inline735 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 tex2html_wrap_inline793  Jy km s tex2html_wrap_inline603 with a linewidth of 420 tex2html_wrap_inline719 60 km s tex2html_wrap_inline603 . 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 tex2html_wrap_inline719 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 tex2html_wrap_inline663 ) conversion factors, the mass of molecular gas M(H tex2html_wrap_inline663 ) could be tex2html_wrap_inline807 M tex2html_wrap_inline749 .

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 tex2html_wrap_inline619 . The velocity scale corresponds to a frequency of 106.570 GHz corresponding to a redshift tex2html_wrap_inline621 .