News & Analysis Physics World  December 2017

French radio telescope to peer into the universe’s ‘dark age’

Listening in When it switches on next year, the New Extension in Nançay Upgrading LOFAR facility will investigate the “dark ages” of the universe. (Belle Dumé)

France is set to open a new 10m low-frequency radio telescope at the Nançay Observatory near Orléans. Dubbed NenuFAR, the observatory is both a standalone instrument as well as a major extension to the existing 150m Low Frequency Radio Array (LOFAR), which is spread across eight European countries and centred in the Netherlands. The telescope will go online in early 2018 when it will be 60% complete.

NenuFAR, which stands for New Extension in Nançay Upgrading LOFAR, is managed by the Paris Observatory, the University of Orléans and the French National Research Council (CNRS). It comprises 1938 antennas built up in 96 mini-arrays. Most will be spread across a distance of 400 m while six of the arrays will cover a distance of 3 km. The telescope will scan the skies over a total operating frequency from around 10 to 87 MHz.

The new instrument will allow scientists to look back to the “dark ages” of the universe and how it evolved just a few million years after the Big Bang. It will also allow them to observe rare transient phenomena such as pulsars, study high-energy cosmic rays and even search for exoplanets and radio emissions from stars.

Currently only half of the antennas have been installed, with researchers still lacking 2m needed to finish the telescope. “The CNRS and Île-de-France regions have contributed to most of the budget, and we hope that we will succeed in obtaining the rest of the funds from the research ministry or the European Research Council to finalize the project,” says Philippe Zarka, astronomer at the Paris Observatory and a NenuFAR principal investigator.

NenuFAR has been officially recognized by the Square Kilometre Array Organization, which is building a giant radio telescope in Australasia and southern Africa. The French research ministry has not yet decided whether France will participate in this project, even though French astrophysicist Catherine Cesarsky has just been elected chair of the SKA board of directors.

Belle Dumé