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Astron. Astrophys. 354, L1-L5 (2000) 1. IntroductionThe recent detections of CO emission at cosmological distances provide hints about the physical structure of newly formed objects (Combes, Maoli & Omont 1999 and reference therein). A measure of the total gas and dust mass is indeed a very useful indicator of the object evolutionary status, because it provides an estimation of the fraction of the galaxy which has yet to be turned into stars at the epoch of observation. At high redshifts such measurements, therefore, provide hints about the occurrence of active star-formation processes and help in investigating models of galaxy formation (Silk & Spaans 1997). Only a handful of distant objects was detected so far in CO, and
most of them appear to be magnified by gravitational lenses
(Table 1). For these objects the mass of molecular gas inferred
from the CO intensities - corrected for gravitational amplification
and using the Galactic CO to H2 conversion factor - turns
out to be Table 1. List of high-redshift objects detected to date in CO. HR10 belongs to the class of objects with very red colours
( In this paper we present CO(2-1) and CO(5-4) observations of HR10 made with the IRAM Plateau de Bure interferometer. The observations are described in Sect. 2, the resulting detection of both lines are presented in Sect. 3, while implications of these measurements are reported in Sect. 4. Throughout the paper, we adopt H0 = 50 Mpc/km/s and q0 = 0.5. ![]() ![]() ![]() ![]() © European Southern Observatory (ESO) 2000 Online publication: January 31, 2000 ![]() |