Colloq Abstract - Riechers
May 11, 2018
11:00am Mountain
Dominik Riechers (Cornell)
The Very Large Array CO Luminosity Density at High Redshift (COLDz) Survey and Prospects for ngVLA Galaxy Surveys
Abstract
Great progress has been made over the past two decades in constraining the star formation history of the universe, but our understanding of how cosmic star formation is fueled by molecular gas at high redshift remains limited to specific, and potentially biased samples of galaxies.
To overcome these limitations, we here present the most recent results from the VLA CO Luminosity Density at High Redshift (COLDz) Survey, a volume scan for CO emission in the early universe, measuring the total gas mass density in galaxies at z~2-3 and 5-7 through "blind" detections of CO J=1-0 and 2-1 emission with the Karl G. Jansky Very Large Array (VLA). The VLA COLDz survey covers a cosmic volume of ~375,000 Mpc^3, making it the largest study of its kind to date. Targeting the low-J CO lines is critical to avoid biases due to gas excitation conditions in different high-redshift galaxy populations, making the VLA ideally suited for such investigations. We will describe under which aspects this measurement of the "cold gas history of the universe" near the peak of cosmic star formation and in the first billion years of cosmic time provides important information on the fueling mechanisms that drive cosmic star formation. This study sets fundamental constraints on the design of planned galaxy surveys in the early universe with the Next Generation Very Large Array (ngVLA).
