Stars Must Have Formed Very Quickly
Max Planck Institute for Astronomy | 2019 Oct 31
Astronomers led by Eduardo Bañados of the Max Planck Institute for Astronomy have discovered a gas cloud that contains information about an early phase of galaxy and star formation, merely 850 million years after the Big Bang. The cloud was found serendipitously during observations of a distant quasar, and it has the properties that astronomers expect from the precursors of modern-day dwarf galaxies. When it comes to relative abundances, the cloud's chemistry is surprisingly modern, showing that the first stars in the universe must have formed very quickly after the Big Bang. ...
When astronomers look at distant objects, they necessarily look back in time. The gas cloud discovered by Bañados et al. is so distant that its light has taken nearly 13 billion years to reach us; conversely, the light reaching us now tells us how the gas cloud looked nearly 13 billion years ago, no more than about 850 million years after the Big Bang. For astronomers, this is an extremely interesting epoch. Within the first several hundred million years after the Big Bang, the first stars and galaxies formed, but the details of that complex evolution are still largely unknown.
This very distant gas cloud was a fortuitous discovery. Bañados, then at the Carnegie Institution for Science, and his colleagues were following up on several quasars from a survey of 15 of the most distant quasars known (z³6.5), which had been prepared by Chiara Mazzucchelli as part of her PhD research at the Max Planck Institute for Astronomy. At first, the researchers just noted that the quasar P183+05 had a rather unusual spectrum. But when Bañados analyzed a more detailed spectrum, obtained with the Magellan Telescopes at Las Campanas Observatory in Chile, he recognized that there was something else going on: The weird spectral features were the traces of a gas cloud that was very close to the distant quasar – one of the most distant gas clouds astronomers have yet been able to identify.
A Metal-poor Damped Lyα System at Redshift 6.4 ~ Eduardo Bañados et al