“Our goal is to survey the entire population of early stars” (Rennan Barkana)
Just 200 million years following the creation of the universe by the Big Bang, the earliest galaxies were relatively small and faint, and probably turned only 5% or less of their gas into stars. Nor did these early galaxies emit radio waves of much greater intensity than modern galaxies.
An international team of astrophysicists led by Anastasia Fialkov, from the University of Cambridge, England, and including Professor Rennan Barkana, Ms Fialkov’s former professor, from the Sackler School of Physics and Astronomy at the University of Tel Aviv (TAU), succeeded for the first time in statistically characterizing the first galaxies in the universe. The results of this innovative study have just been published in the prestigious journal Nature Astronomy sous le titre “Astrophysical constraints from the SARAS 3 non-detection of the cosmic dawn sky-averaged 21-cm signal”.
“We are trying to understand the time of the first stars in the universe, known as the ‘cosmic dawn’, around 200 million years following the Big Bang.” The James Webb Space Telescope, for example, can’t really see these stars. It might only detect a few particularly bright galaxies from a somewhat later period. Our goal is to survey the entire population of early stars,” Rennan Barkana said.
“Hydrogen atoms naturally emit light at a wavelength of 21 cm, which is in the radio wave spectrum. We are using hydrogen as a detector in our search for the first stars. If we can detect the effect of stars on hydrogen, we will know when they were born and in what types of galaxies,” he added.