The galaxy, shown in this artist's impression, is 1-2%
the Milky Way's mass
An international team of astronomers has
detected the most distant galaxy yet.
The galaxy is about 30 billion light-years away and is
helping scientists shed light on the period that
immediately followed the Big Bang.
It was found using the Hubble Space Telescope and its
distance was then confirmed with the ground-based
Keck Observatory in Hawaii.
The study is published in the journal Nature.
Because it takes light so long to travel from the outer
edge of the Universe to us, the galaxy appears as it was
13.1 billion years ago.
Lead researcher Steven Finkelstein, from the University
of Texas at Austin, US, said: "This is the most distant
galaxy we've confirmed. We are seeing this galaxy as it
was 700 million years after the Big Bang."
The far-off galaxy goes by the catchy name of
z8_GND_5296.
Astronomers were able to measure how far it was from
Earth by analysing its colour.
Because the Universe is expanding and everything is
moving away from us, light waves are stretched. This
makes objects look redder than they actually are.
Astronomers rate this apparent colour-change on a
scale that is called redshift.
They found that this galaxy has a redshift of 7.51,
beating the previous record-holder, which had a
redshift of 7.21.
This makes it the most distant galaxy ever found.
z8_GND_5296 is churning out stars at a remarkable
rate, say astronomers
The system is small: about 1-2% the mass of the Milky
Way and is rich in heavier elements.
But it has a surprising feature: it is turning gas and dust
into new stars at a remarkable rate, churning them out
hundreds of times faster than our own galaxy can.
It is the second far-flung galaxy known that has been
found to have a high star-production rate.
Prof Finkelstein said: "One very interesting way to learn
about the Universe is to study these outliers and that
tells us something about what sort of physical
processes are dominating galaxy formation and galaxy
evolution.
"What was great about this galaxy is not only is it so
distant, it is also pretty exceptional."
He added that in the coming years, astronomers are
likely to discover even more distant galaxies when
Nasa's James Webb Space Telescope (JWST) is launched
and other ground-based telescopes come online.
Commenting on the research, Dr Marek Kukula, Public
Astronomer at the Royal Observatory Greenwich, told
BBC News: "This, along with some other evidence,
shows that there are already quite surprisingly evolved
galaxies in the very early Universe .
"This high star-formation rate maybe is a clue as to
why these galaxies can form so quickly."
Prof Alfonso Aragon-Salamanca, from the University of
Nottingham, added: "This is an important step forward,
but we need to continue looking for more.
"The further away we go, the closer we will get to
discovering the very first stars that ever formed in the
Universe. The next generation of telescopes will make
this possible."
But Dr Stephen Serjeant from the Open University said:
"Chasing ultra-high redshift galaxies is a very exciting
but equally very difficult game, and many claims of
extremely distant galaxies have since turned out to be
more nearby interlopers."
Comments
Post a Comment