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New experiment to shed light on the Cosmic Dawn

BY DR HILARY KAY (THE UNIVERSITY OF MANCHESTER – UK)

An experiment designed to detect and study the Cosmic Dawn’s radio signal has found a home 15km south of where the core of the SKA-Mid telescope will be located in South Africa. The Radio Experiment for the Analysis of Cosmic Hydrogen (REACH), led by the University of Cambridge and Stellenbosch University, brings together radio astronomers and engineers from 16 institutions across four continents.

Occurring at around 378,000 years after the Big Bang, the Cosmic Dawn indicates the time when the very first stars in the Universe appeared and forms one of the core science goals of the SKA telescopes. Visible as a dip in neutral hydrogen emission at low radio frequencies, the Cosmic Dawn signal is many thousands of times weaker than foreground emission, making it challenging to reliably detect and analyse.

The REACH team will use novel techniques to understand the components that make up the Cosmic Dawn signal, employing both a wideband dipole and a log spiral antenna to identify instrumental effects. They will perform joint fitting of the data using models of the cosmological signal, the foreground emission, and instrumental effects, helping to shed light on previous Cosmic Dawn observations.

“We are truly excited about the prospect of starting observations in 2022,” said REACH’s principal investigator from the University of Cambridge, Dr Eloy de Lera Acedo. “We have been preparing our data analysis and calibration pipelines during the pandemic and are ready to shine some light on our understanding of the Cosmic Dawn.”

REACH is expected to be operational in mid-2022, providing timely information to help inform observing strategies and data analysis for the SKAO and future observatories. The experiment is sponsored by the Kavli Institute for Cosmology in Cambridge, Stellenbosch University, South Africa’s National Research Foundation, the Cambridge ALBORADA fund and the UK’s Science and Technology Facilities Council (STFC).

The REACH team during installation of the first antenna.

Credit: Eloy de Lera Acedo – University of Cambridge

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