Dr. Tzu-Ching Chang, Jet Propulsion Laboratories

21cm Cosmology
October 22, 2021


The redshifted 21-cm emission from neutral hydrogen has emerged as a powerful probe for cosmology and fundamental physics. Because hydrogen is the most abundant baryonic element in the universe, a large fraction of the observable universe can be mapped in three-dimensions using the 21-cm emission. We can observe it from the present day all the way to the so-called Dark Ages, a period preceding the formation of the very first stars more than 13 billion years ago. I will discuss current ground-based experimental efforts to map this emission in the radio frequencies and discuss the prospects for a space mission concept such as the FARSIDE probe study.


Dr. Tzu-Ching Chang

received her PhD in 2003 at Columbia University, where she used the FIRST Radio Survey to make and exploit cosmic shear measurements of large scale structures in the universe. She has worked on theory and data analysis of 21cm Cosmology and Line Intensity Mapping, exploring probes of cosmic dawn and reionization at high redshift and large-scale structure at low redshift. She is the PI of GBT-HIM, an 800MHz focal-plane array for the Green Bank Telescope for a Baryon Acoustic Oscillation HI survey at z~1, and is
involved in TIME, a [CII] intensity mapper tracing the reionization process at 6<z<9.