Molecular and atomic gas in z=2.49 protocluster galaxies

Cold gas observations of high redshift galaxies have been one of the major drivers of recent ALMA studies. But it is poorly known whether the properties of cold gas (e.g., gas content, gas excitation, and gas kinematics) are different in various environments at high redshifts such as in proto-clusters, compared to general fields. We present ALMA observations of two CO lines (CO (4-3) and CO (3-2)) and the lower atomic carbon line transition ([CI](1-0)) toward star-forming galaxies. They are selected by H-alpha line and/or sub-mm continuum emission in a proto- cluster at z=2.49 thus some of them are undergoing dusty star-forming phases. This work is one of few pioneering studies on z>2 proto-clusters, with a dozen of star-forming galaxies mostly on the main-sequence detected in CO. We discuss the properties of cold gas by exploring the gas content and the gas kinematics from individual detections and the stacking analysis. Based on the observations, we address that larger volume observations are needed for better statistics in different environments to understand the role of environments in galaxy evolution.