Cosmology & Gravity Working Group — Livia Vallini (NORDITA)

Wednesday 18 Jan 2017, 13:15 → 14:00 Europe/Stockholm

C6:1046 (aka FC61)

Zooming on first galaxies: the ISM at the cosmic dawn

The properties of the interstellar medium (ISM) of the first galaxies are still poorly constrained. The ISM is a very complex environment composed by different structures that are the result of the continuous interplay between radiative and dynamical processes that take place on different scales. We cannot understand the large-scale dynamics of the ISM without profound knowledge of the underlying quantum physical and chemical processes. Vice versa, the dynamics on large galactic scales determine the local properties of the different phases of the ISM, such as their ability to cool and collapse, and to give birth to new stars. In this talk I will provide an overview regarding the semi-analytical models that I developed to describe the relative abundance of various gas phases in the ISM of the first galaxies. The models include a full treatment of the effects of stellar far-ultraviolet photons on the structure, chemistry, and thermal balance of the ISM. Once coupled with high-resolution cosmological simulations, they allowed to successfully interpret various far-infrared line detections from the cold gas in galaxies at z>6 that in the last few years have been obtained with the Atacama Large Milimeter Array (ALMA).