“Out There”—Most-Distant Known Galaxy Detected

GN-z11s Galaxy

 

An international team of astronomers has confirmed the most-distant known galaxy, GN-z11s, a hefty13.4 billion light years away, indicating it was shining just 400 million years or so after the Big Bang, along with a brief ultraviolet flare of a powerful gamma ray burst–a phenomenon never before observed in the extremely early universe–that was detected in data from the Keck 1 telescope at the W.M. Keck Observatory in Hawaii. The astronomers used deep spectroscopic analysis, discovering an unusual higher-than-expected concentrations of elements heavier than hydrogen and helium, ruling out a first-generation galaxy.

An Anomaly

“The more we learn about the universe’s earliest objects, the better we can understand how the structure of our cosmos was shaped,” said Carnegie researcher and team member Gregory Waith about the anomaly — in first-generation galaxies, massive first-generation stars had not had time to live their lives, go supernova and seed the environment with the heavier elements seen in GN-z11. How the galaxy fits into the early stages of cosmic evolution remains to be seen.

Astronomers predict that volume of space-time within range of our telescopes—‘the known universe’—is only a tiny fraction of the aftermath of the big bang, with far more galaxies unobservable, located beyond the horizon, unobservable. “Each of which (along with any civilizations it hosts) will evolve rather like our Milky Way,” says astrophysicist, Martin Rees.

One of the primary scientific goals of the next generation telescopes, including the Giant Magellan Telescope under construction at Carnegie’s Las Campanas Observatory, is to understand the period of cosmic reionization which lasted several hundred million years and represents one of the most important phase transitions of the history of the universe. However, it is very difficult for existing telescopes to detect spectra from such distant galaxies, which is what makes this discovery of GN-z11 so exciting.

“Great Known Unknown” –The Number of Galaxies Beyond the Observable Universe

An earlier anomaly was announced in May 2020 when a new discovery was revealed by the ALMA Observatory in Chile of a massive rotating disk galaxy, the Wolfe Disk –the most distant rotating disk galaxy–observed when the universe was only ten percent of its current age, as early as 1.5 billion years after the Big Bang, challenging the traditional models of galaxy formation. In most galaxy formation hypotheses, galaxies only start to show a well-formed disk around 6 billion years after the Big Bang.

The Webb Will Peer Farther Back Into Time 

The infrared eye of NASA’s James Webb Space Telescope, set to launch in 2021 will primarily look at the Universe in the infrared from 1.5 million kilometers distant at the second Lagrange (L2) point where the Webb’s solar shield will block the light from the Sun, Earth, and Moon, while Hubble studies it primarily at optical and ultraviolet wavelengths (though it has some infrared capability). Webb has a much bigger mirror than Hubble, which means that Webb can peer farther back into time and the early universe than Hubble is capable of doing.

The observations are described in two papers published in the journal Nature Astronomy.

The Daily Galaxy, Sam Cabot, via Carnegie Institution for Science

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