Early-universe prequel: Galaxies in distant space
We all know our universe accommodates gigantic galaxy clusters in space. Every galaxy is manufactured from hundreds of thousands to billions of stars. And every cluster is manufactured from lots of to hundreds of galaxies, sure collectively by gravity. And the clusters group into even-larger superclusters, with huge voids in between. Now take into account that trying distant in space is identical as trying again in time. That’s why we are able to use probably the most highly effective of contemporary telescopes to see into the early universe, and see an early-universe prequel – a precursor, a forerunner – to one of many enormous galaxy clusters we see in the present day.
In different phrases, what you see above is a picture – from the brand new Webb House Telescope, which launched in late 2021 and was positioned on the L2 point within the Earth-sun system – of seven exceedingly distant galaxies. They’re younger galaxies within the early universe, confirmed at a distance that astronomers check with as redshift 7.9. That distance away in space correlates to 650 million years after the Big Bang, the occasion that gave rise to our universe 13.8 billion years in the past. The European House Company said in late April:
This makes them the earliest galaxies but to be spectroscopically confirmed as a part of a growing cluster.
These outcomes have been printed in The Astrophysical Journal Letters.
How astronomers seen these galaxies
Webb wasn’t the primary space telescope to see these galaxies. The Hubble House Telescope’s Frontier Fields program – which ran from 2013 to 2017 – additionally noticed them. It was Frontier Fields that first established the galaxies as candidates for additional commentary. ESA mentioned:
Frontier Fields devoted Hubble time to observations utilizing gravitational lensing, to look at very distant galaxies intimately. Nevertheless, as a result of Hubble can not detect mild past near-infrared, there may be solely a lot element it may well see. Webb picked up the investigation, specializing in the galaxies scouted by Hubble and gathering detailed spectroscopic knowledge along with imagery.
See a Wikipedia entry containing a list of deep fields, in part from Frontier Fields
What Webb brings to the desk
The James Webb House Telescope is a global collaboration amongst NASA, the European House Company (ESA), and the Canadian House Company (CSA). ESA said:
Astronomers used Webb’s Close to-Infrared Spectrograph (NIRSpec) instrument to exactly measure the distances and decide that the galaxies are a part of a growing cluster. Galaxy YD4, beforehand estimated to be at an additional distance based mostly on imaging knowledge alone, was in a position to be extra precisely positioned on the similar redshift as the opposite galaxies.
Earlier than Webb, astronomers didn’t have excessive decision imaging or spectral infrared knowledge accessible to do any such science.
At excessive distances, astronomers use the redshift reference to account for the truth that, because the universe expands, wavelengths of sunshine are stretched and ‘shifted’ to redder wavelengths, that are longer. Shorter wavelengths, for instance ultraviolet and X-ray, are towards the bluer finish of the electromagnetic spectrum. So excessive distances within the early universe are referenced by how a lot the sunshine emitted there was shifted because it travelled by way of space to be detected by a telescope.
Backside line: We all know our universe consists of gigantic galaxy clusters in space. And we all know that trying distant in space equals trying again in time. Right here’s an early-universe prequel to an enormous galaxy cluster.
