The brightest galaxy ever found is actually a "fraud"

Ultra-bright galaxies in the early universe are perhaps less common than scientists thought, according to new research.

The researchers used the Hubble Space Telescope to observe two galaxies so far away that we see them more than 13 billion years ago, when the universe was young

L & # 39; Study team of the most brilliant reionizing galaxies (BoRG) discovered that a galaxy was a brilliant source seen over 13 billion years ago, as expected. But the other was an "impostor" – a relatively close galaxy taken for a very long way because of its red color.

The effect known as redshift gives distant galaxies distinct colors that can indicate how far away they are. But some relatively close galaxies have falsely similar colors, which gives some uncertainty to their estimated distance.

The researchers say that this discovery – that the most brilliant galaxy candidate known in the primitive universe is essentially a fraud – has profound implications for models of how galaxies

BoRG project

BoRG is designed to find bright early galaxies. The BoRG project, led by Michele Trenti, an associate professor at the University of Melbourne and ARC's Center of Excellence for Sky Astrophysics, leverages Hubble's ability to use multiple cameras at once.

Trenti said that To use it, the BoRG team used the Wide Field Camera 3 camera, very sensitive, to observe a random area of ​​the sky for a few hours. He says that repeating this more than 100 times has resulted in a rich set of data covering unrelated parts of the universe, maximizing the chances of landing on a rare and bright galaxy

. far away allows us to take pictures of galaxies … "

" Since Hubble's prime time is so scarce and oversubscribed, the BoRG survey is an ideal opportunity to carry out cutting-edge science at no additional cost "said Trenti. "It's essentially doubling the productivity of an already amazing telescope."

The researchers first observed both galaxies in this study as part of the BoRG survey and reported the observations in a 2016 paper.

Let's look again at these sources in order to take a more detailed measurement of the colors of the two galaxies, thus refining their estimated distances. One of them was more than 13 billion years old, while the universe accounted for only 5% of its current age.

Young and brilliant astrophysicist Rachael Livermore, who led the research following the discovery of BoRG, says this galaxy was incredibly brilliant.

"This makes it an ideal target for further study so that we can truly understand what is happening inside galaxies in the early years of the universe," says Livermore.

The second galaxy was considered the brightest galaxy discovered in the 650 million years after the Big Bang, but has turned out to be a fraud.

"Looking far away basically allows us to take pictures of baby galaxies, so we can see how they started and then understand how they grew up in the types of galaxies we see today," says Livermore

Fuel tanks extend the star phase of young galaxies

"Now that we have better color measurement, now it looks like if the brightest galaxy is relatively close – we we see it only 9 billion years ago, whereas it was previously estimated at 13 billion. "

These galaxies are a natural target for Hubble's successor, James Webb's Space Telescope. which should be launched in 2021. The new telescope is designed to find and characterize very early galaxies and the BoRG team hopes to use it for further research.

The latest study de is published in the Astrophysical Journal Letters

The ARC Center of Excellence for Three-dimensional Sky Astrophysics (ASTRO 3D), a research center of excellence from the Australian Research Council (ARC) and six universities The National University, the University of Sydney, the University of Melbourne, the University of Technology of Swinburne, the University of Western Australia and Curtin University partially funded the study.

Source: University of Melbourne