The z-GAL survey

Abstract

The z-GAL survey observed 137 bright Herschel-selected galaxies with the IRAM Northern Extended Millimeter Array (NOEMA) to measure their spectroscopic redshift. It detected several multiple sources and secured the spectroscopic redshift of a total of 165 individual galaxies over the range 0.8 < z < 6.5. The wealth of information provided by the NOEMA spectra allowed us to study the physical properties of these galaxies. By modelling their spectral energy distributions, we determined their dust mass, Mdust, temperature, Tdust, and emissivity index, βdust and found a significant anti-correlation between Tdust and βdust. Using the detected 12CO lines, we derived the molecular gas mass of the z-GAL sources. Combining the molecular lines and the dust continuum emission, we computed their gas depletion timescales, τdep: the z-GAL sample consists mainly of powerful starbursts with τdep in the range between 0.1 and 1.0 Gyr, while only ~ 25% belongs to the ‘main sequence’ of star forming galaxies.