An ALMA view of the first galaxies

The most intriguing question of modern extra-galactic astronomy is to locate and study the first galaxies in order to determine when they emerged from the dark ages, what are their physical properties and what role do they play in governing the transition of intergalactic hydrogen from a neutral state to one that is ionised. Measures of the optical depth of electron scattering by the Planck satellite indicates this `cosmic reionisation’ was a fast process occurring relative late over the redshift interval 12 8 galaxies combining Hubble, Spitzer and ALMA data