EDP Sciences
Free access
Volume 477, Number 3, January III 2008
Page(s) 775 - 779
Section Extragalactic astronomy
DOI http://dx.doi.org/10.1051/0004-6361:20078294

A&A 477, 775-779 (2008)
DOI: 10.1051/0004-6361:20078294

CO investigation of z = 0.4-1.5 galaxies

A.-L. Melchior1, 2 and F. Combes1

1  LERMA, Observatoire de Paris, UMR 8112, 61 avenue de l'Observatoire, 75014 Paris, France
    e-mail: [A.L.Melchior;Francoise.Combes]@obspm.fr
2  Université Pierre et Marie Curie - Paris 6, 4 place Jussieu, 75252 Paris Cedex 05, France

(Received 17 July 2007 / Accepted 2 November 2007 )

We report on the results of an IRAM-30 m search for CO emission lines in three galaxies at intermediate redshifts. The idea was to investigate the molecular content of galaxies that are bright in the infrared at z=0.4-1.5, a redshift desert for molecular line studies because poorly investigated as yet. We integrated 8-10 h per source and did not succeed in detecting any of the sources. From our upper limits, we were able to constrain the molecular gas content in these systems to less than 4 to 8 $\times$ $10^9~M_\odot$, assuming a CO-to-H2 conversion factor ( $\alpha=0.8~M_\odot$/(K km s-1 pc2)). We stress the current difficulty of selecting sources with a detectable molecular content, a problem that will be faced by the ALMA First Science projects.

Key words: submillimeter -- infrared: galaxies -- radio lines: galaxies -- galaxies: general -- methods: observational

© ESO 2008