SIMBAD references

We present new IRAM Plateau de Bure interferometer (PdBI) 1.3mm continuum observations at ∼1.5'' resolution of 28 submillimeter galaxies (SMGs), previously discovered with the 870 µm bolometer LABOCA at the APEX telescope from the central 0.7deg² of the COSMOS field. Nineteen out of the 28 LABOCA sources were detected with PdBI at a >3σ level of ≃1.4mJy/beam. A combined analysis of this new sample with existing interferometrically identified SMGs in the COSMOS field yields the following results: i) >15%, and possibly up to ∼40% of single-dish detected SMGs consist of multiple sources; ii) statistical analysis of multi-wavelength counterparts to single-dish SMGs shows that only ∼50% have real radio or IR counterparts; iii) ∼18% of interferometric SMGs have either no multi-wavelength counterpart or only a radio-counterpart; and iv) ∼50-70% of z>3 SMGs have no radio counterparts (down to an rms of 7-12µJy at 1.4GHz). Using the exact interferometric positions to identify the multi-wavelength counterparts allows us to determine accurate photometric redshifts for these sources. The redshift distributions of the combined and the individual 1.1mm and 870µm selected samples shows a higher mean and a broader width than those derived in previous studies. This study finds that on average brighter and/or mm- selected SMGs are located at higher redshifts, consistent with previous studies. The mean redshift for the 1.1mm selected sample (z=3.1±0.4) is tentatively higher than that for the 870µm selected sample (z=2.6±0.4). Based on our nearly complete sample of AzTEC 1.1mm SMGs in a 0.15deg² area, we infer a higher surface density of z>4 SMGs than predicted by current cosmological models. In summary, our findings imply that interferometric identifications at (sub-)millimeter wavelengths are crucial to build statistically complete and unbiased samples of SMGs.