Seminar: The 21cm Forest

Dr Katherine J. Mack 

Kavli Institute for Cosmology, Cambridge/Institute of Astronomy

Download the pdf poster.

Future observations of the 21cm forest -- neutral hydrogen absorption against high-redshift radio sources -- will allow us to trace out the structure of the pre-reionization intergalactic medium (IGM), provided bright radio sources can be found at sufficiently high redshift.

I will present a calculation of the expected 21cm forest as might be observed in coming years and show how statistical detection techniques could be used to overcome the low signal-to-noise. I will also discuss the trade-off between the availability of large populations of high-redshift background radio sources and the requirement that the IGM be sufficiently neutral for strong absorption.