Vol. 552
In section 4. Extragalactic astronomy

Towards a resolved Kennicutt-Schmidt law at high redshift

Understanding star formation in the distant Universe is one of the major challenges in present-day observational astronomy. In this paper the authors present the results of a detailed study using observations from the IRAM Plateau de Bure interferometer and the Keck DEEP2 spectroscopic survey of four massive star-forming galaxies at z~1.2. Resolving the individual star-forming regions in these galaxies is impossible, but combining optical spectroscopy with CO observations enables the determination of both the gas and the star formation surface densities of ensembles of clumps that constitute galaxies at these high redshifts. The integrated CO line luminosity is directly proportional to the total gas mass, and the star formation rate is deduced from the [OII] recombination line. The authors thus derive a spatially resolved Kennicutt-Schmidt relation for a scale of -8 kpc in each of these galaxies. The data indicate that the average time it will take for each galaxy to use up all its gas will be around 1.9 Gyr, but there are large variations in this value within each galaxy.