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The ultra-bright galaxies of the early universe are perhaps less common than originally thought, revealed a new study using the Hubble Space Telescope.
Researchers led by a team from the University of Melbourne and ARC's Center of Excellence for 3-D Sky Astrophysics used Hubble to observe two galaxies considered so far away that we let's see more than 13 billion years in time. was young
In a research published in the Astrophysical Journal Letters the brightest survey team of reionizing galaxies (BoRG) found that a galaxy was a brilliant source seen there are over 13 billion years old. 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 said that this discovery – that the most brilliant galaxy known in the primitive universe is essentially a fraud – has profound implications for galaxy models. formed while the universe was in its infancy.
BoRG is designed to find bright early galaxies. The BoRG project, led by Associate Professor Michele Trenti of the University of Melbourne and the ARC Center of Excellence for Sky Astrophysics, leverages Hubble's ability to utilize multiple cameras simultaneously.
the BoRG team used the highly sensitive Wide Field Camera 3 camera to observe a random area of the sky for a few hours. He said that repeating this more than 100 times accumulated a rich data set that covers independent parts of the universe, maximizing the chances of landing a rare and bright young galaxy
"Since Hubble's primary time is so rare and oversubscribed, the BoRG survey represents this is an ideal opportunity to conduct advanced research at no additional cost, "said Professor Trenti. "It's essentially doubling the productivity of an already amazing telescope."
The two galaxies in this study were observed for the first time as part of the BoRG study and published in 2016 in a paper directed by Dr. Valentina Calvi of the Baltimore Space Telescope Science.
The last study used Hubble to examine these sources again in order to take a more detailed measurement of the colors of the two galaxies, thus refining their estimated distances. The astrophysicist at the University of Melbourne, Rachael Livermore, who was leading the research following the discovery of BoRG, said that this galaxy was incredibly brilliant compared to the astrophysics of the University from Melbourne. peers. "This makes it a perfect target for further study, so that we can truly understand what is happening inside galaxies in the early years of the universe," said Dr. Livermore.
The second galaxy was the brightest galaxy discovered in the first 650 million years after the Big Bang, but 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 understand" Now that we have better color measurement, it now seems like the brightest of galaxies be relatively close – we see it only nine billion years ago, whereas we previously thought about 13 billion. "
These galaxies are a natural target for Hubble's successor, the space telescope James Webb, to be launched in 2021. The new telescope is designed to find and characterize early laxies and the BoRG team hopes to use it for further research.
Learn more:
The glare of Hubble galaxies
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