Vol. 548
In section 4. Extragalactic astronomy

Millimeter imaging of submillimeter galaxies in the COSMOS field: redshift distribution

From 27 submillimeter galaxies (SMGs) discovered with low spatial resolution at 0.9 mm with APEX in the COSMOS field, 18 have been detected with Plateau de Bure interferometer with a resolution of 1.5” in the continuum at 1.3mm. These detections show that 15% of these SMGs consist of multiple sources, almost 70% of the multi-wavelength identifications made on the single-dish SMGs were correct. The identification of the sources allows one to derive their photometric redshift. The mean redshift found here is slightly higher than in previous samples, and the 1.1mm selected sources have a higher (3.1) mean redshift than the 0.9mm selected sources (2.6). The results also imply a surface density of z>4 SMGs, which is higher than predicted by current cosmological models.