The thermal state of the intergalactic medium 9-12 billion years ago

This work presents an investigation of the thermal state of the tenuous gas between galaxies, called the intergalactic medium. It is focused on measuring the temperature evolution of this cosmic gas during the second reionization phase of the Universe that happened between 9 and 12 billion years ago. During this event the radiation emitted by powerful objects, called quasars, profoundly changed the properties of the intergalactic medium that, in turn, determine the conditions for the formation and evolution of the structures that populate our Universe. Our measurements show evidence for this second reionization and track its final stages.