The abstract is as follow:
As the main repository of baryons in the universe, cosmic gas provides important clues to the formation and evolution of the large scale structure. I will discuss several projects related to the two "missing baryons" problems, with a focus on understanding the cosmic structure formation and evolution through its gaseous content. At large scale, the "missing baryons" problem refers to the discovery that the observed baryonic matter in the local universe accounts for less than 50% of the total baryons. At small scale, the second ”missing baryons” problem refers to the fact that the cold baryon fraction in Milky-Way size galaxies is well-below the mean cosmic baryon fraction. I will discuss our recent progress toward solving both puzzles. I will also discuss how answers to these questions help understand the circumgalactic medium, the interface between galaxy and the intergalactic medium, and its role in regulating galaxy formation and evolution.