CO (4-3) and dust emission in two powerful high-z radio galaxies, and CO lines at high redshifts

Padeli P. Papadopoulos, H. J.A. Röttgering, P. P. Van Der Werf, S. Guilloteau, A. Omont, W. J.M. Van Breugel, R. P.J. Tilanus

Research output: Contribution to journalArticlepeer-review

126 Scopus citations


We report the detection of submillimeter emission from dust at 850 μm and of the 12CO J = 4-3 line in the two distant powerful radio galaxies 4C 60.07 (z = 3.79) and 6C 1909 + 722 (z = 3.53). In 4C 60.07, the dust emission is also detected at 1.25 mm. The estimated molecular gas masses are large, of the order of ∼(0.5-1) × 1011 M⊙. The large far-infrared (FIR) luminosities (LFIR ∼ 1013 L⊙) suggest that we are witnessing two major starburst phenomena, while the observed large velocity widths (ΔVFWHM ≳ 500 km s-1) are characteristic of mergers. In the case of 4C 60.07, the CO emission extends over ∼30 kpc and spans a velocity range of ≳1000 km s-1. It consists of two distinct features with FWHM of ≳550 km s-1 and ∼150 km s-1, and line centers separated by ≳700 km s-1. The least massive of these components is probably very gas rich, with potentially ≳60% of its dynamical mass in the form of molecular gas. The extraordinary morphology of the CO emission in this object suggests that it is not just a scaled-up version of a local ultraluminous infrared galaxy, and it may be a formative stage of the elliptical host of the residing radio-loud active galactic nucleus (AGN). Finally, we briefly explore the effects of the wide range of gas-excitation conditions expected for starburst environments on the luminosity of high-J CO lines and conclude that in unlensed objects, CO (J + 1 → J), J + 1 > 3 lines can be significantly weak with respect to CO J = 1-0, and this can hinder their detection even in the presence of substantial molecular gas masses.

Original languageEnglish (US)
Pages (from-to)626-636
Number of pages11
JournalAstrophysical Journal
Issue number2 PART 1
StatePublished - Jan 10 2000
Externally publishedYes


  • Galaxies: ISM
  • Galaxies: active
  • Galaxies: formation

ASJC Scopus subject areas

  • Astronomy and Astrophysics
  • Space and Planetary Science


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