2016/02/29 by Anastasia Fialkov, Abraham Loeb
Physics and Astronomy · #Astrophysics #Cosmic microwave background #Cosmology and Gravitation Theories #Electron #Galaxy #Measure (data warehouse) #Optical depth #Optics #Photon #Physics #Pulsars and Gravitational Waves Research #Quantum mechanics #Radio Astronomy Observations and Technology #Redshift #Reionization #astro-ph.CO #astro-ph.HE
paper · pdf · doi:10.1088/1475-7516/2016/05/004
published as JCAP (2016) 05 004 · 6 pages, 3 figures, 1 table
openalex publication_date 2016/05/03 · arxiv created 2016/11/02 · arxiv updated 2016/11/03 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/05
The dispersion measure of extragalactic radio transients can be used to measure the column density of free electrons in the intergalactic medium. The same electrons also scatter the Cosmic Microwave Background (CMB) photons, affecting precision measurements of cosmological parameters. We explore the connection between the dispersion measure of radio transients existing during the Epoch of Reionization (EoR) and the total optical depth for the CMB showing that the existence of such transients would provide a new sensitive probe of the CMB optical depth. As an example, we consider the population of FRBs. Assuming they exist during the EoR, we show that: (i) such sources can probe the reionization history by measuring the optical depth to sub-percent accuracy, and (ii) they can be detected with high significance by an instrument such as the Square Kilometer Array.