W.M. Keck Observatory | 2018 Dec 17
Rare Relic is One of Only Three Fossil Clouds Known in the Universe
A relic cloud of gas, orphaned after the Big Bang, has been discovered in the distant universe by astronomers using the world’s most powerful optical telescope, the W. M. Keck Observatory on Maunakea, Hawaii.Simulation of galaxies and gas in the universe. Within the gas in the (blue)
filaments connecting the (orange) galaxies lurk rare pockets of pristine gas –
vestiges of the Big Bang that have somehow been orphaned from the explosive,
polluting deaths of stars, seen here as circular shock waves around some orange
points. Credit: IllustrisTNG/TNG Collaboration
The discovery of such a rare fossil, led by PhD student Fred Robert and Professor Michael Murphy at Swinburne University of Technology, offers new information about how the first galaxies in the universe formed.
“Everywhere we look, the gas in the universe is polluted by waste heavy elements from exploding stars,” says Robert. “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.” ...
Robert and his team used two of Keck Observatory’s instruments – the Echellette Spectrograph and Imager (ESI) and the High-Resolution Echelle Spectrometer (HIRES) – to observe the spectrum of a quasar behind the gas cloud.
The quasar, which emits a bright glow of material falling into a supermassive black hole, provides a light source against which the spectral shadows of the hydrogen in the gas cloud can be seen. ...
Exploring the Origins of a New, Apparently Metal-Free Gas Cloud at z = 4.4 ~ P. Frédéric Robert et al
- Monthly Notices of the RAS (online 06 Dec 2018) DOI: 10.1093/mnras/sty3287
arXiv.org > astro-ph > arXiv:1812.05098 > 12 Dec 2018