Invited Presentation

The Transition from Atomic to Molecular ISM and Observational Opportunities in the Next 5 Years

The Transition from atomic to molecular phase in the ISM is a key step in setting the initial conditions of star formation. Such transition is a key process that just begin to be implemented in cosmological and galaxy evolution simulations.

We have provided critical constraints for these modeling efforts through observational studies of Milky way gas clouds.
Our results including the time scale of the HI-H2 transition and the existence of dark gas.

In 5 years, China will operate the largest radio telescope, namely, the Five-hundred-meter Aperture Spherical radio Telescope (FAST). Together with development efforts in space radio astronomy and international collaboration, these projects will advance our understanding of HI-H2 transition, and in turn, the history of gas in the universe, greatly.