Astronomers have recently discovered a relic cloud of gas, orphaned next to Big Bang in the distant universe. The discovery of such a rare fossil could offer new insights about first galaxy formation in the universe.
This discovery is made by using world’s most powerful optical telescope, the W. M. Keck Observatory on Maunakea, Hawaii.
PhD student Fred Robert said, “Everywhere we look, the gas in the universe is polluted by waste heavy elements from exploding stars. But this particular cloud seems pristine, unpolluted by stars even 1.5 billion years after the Big Bang.”
“If it has any heavy elements at all, it must be less than 1/10,000th of the proportion we see in our Sun. This is extremely low; the most compelling explanation is that it’s a true relic of the Big Bang.”
Scientists used two of Keck Observatory’s instruments – the Echellette Spectrograph and Imager (ESI) and the High-Resolution Echelle Spectrometer (HIRES). Using instruments, they observed the spectrum of a quasar behind the gas cloud, which emits a bright glow of material falling into a supermassive black hole. This gives a light source against which the spectral shadows of the hydrogen in the gas cloud can be seen.
Robert said, “We targeted quasars where previous researchers had only seen shadows from hydrogen and not from heavy elements in lower-quality spectra. This allowed us to discover such a rare fossil quickly with the precious time on Keck Observatory’s twin telescopes.”
Until now, only two other fossil clouds known were discovered in 2011- Professor Michele Fumagalli of Durham University, John O’Meara, formerly a professor at St. Michael’s College. Now the new Chief Scientist at Keck Observatory, and Professor J. Xavier Prochaska of the University of California, Santa Cruz.
O’Meara said, “The first two were serendipitous discoveries, and we thought they were the tip of the iceberg. But no one has discovered anything similar – they are clearly very rare and difficult to see. It’s fantastic to finally discover one systematically.”
“It’s now possible to survey for these fossil relics of the Big Bang,” says Murphy. “That will tell us exactly how rare they are and help us understand how some gas formed stars and galaxies in the early universe, and why some didn’t.”
The results will be published in the journal Monthly Notices of the Royal Astronomical Society.