Infant galaxy discovered with help of natural cosmic telescope - study
A rotating infant galaxy from the early days of the universe has been observed by astronomers for the first time, and it could considerably change the way in which we understand the universe.
A spiral galaxy known as NGC 1433 is seen in an undated image captured by the NASA/ESA Hubble Space Telescope (photo credit: REUTERS)
A rotating infant galaxy a mere fraction of the size of the Milky Way has been observed by astronomers at Ben-Gurion University of the Negev in a new study.
This
"baby galaxy," named RXCJ0600-z6, was spotted by the Atacama Large
Millimeter/submillimeter Array (ALMA) telescope in Chile, which uses
gravitational lensing to find galaxies formed in the early days of the
universe.
The
galaxy in question was estimated to have a mass of 2-3 million solar
masses, meaning 2-3 million times more mass than the Sun. However, this
is just 1/100th the size of the Milky Way, which is around 1.5 trillion
solar masses.
The
size is an important factor, as it is precisely because of their small
sizes that many galaxies in the early days of the universe remain
undetected by scientists. The light coming from them - light and size
are linked - simply wasn't bright enough for telescopes on Earth to
actually visualize them.
However,
because ALMA uses gravitational lensing the brightness from RXCJ0600-z6
was highly magnified. This made it "an ideal target for studying the
properties and structure of typical baby galaxies," University of
Cambridge Kavli Senior Fellow Nicolas Laport said in a statement.
Gravitational
lensing is a natural phenomenon in which the gravity of a massive body,
such as a galaxy or a galaxy cluster, bends the light that is being
emitted from a distant object. This allows the gravity of the massive
object to act like a lens, and through this method the light of the
distant object is intensified and its shape is enlarged.
ALMA
observed RXCJ0600-z6 as it was when the universe itself was around 900
million years old – a mere 7% of its current age. Upon further analysis
of the data, it was determined that a part of this source is seen 160
times brighter than it is in reality.
Zooming in on the Active Galaxy NGC 1433 - Mar.17, 2016
Finding galaxies such as this one is crucial and could impact some
of our most fundamental knowledge of the universe. Galaxies formed in
the early days of the universe are much smaller and therefore faint and
difficult to detect. The more knowledge and data we can accumulate on
these early galaxies the better, as it will allow us to gain a complete picture of how they form and evolve over time as the universe expands.
Proof
of the importance of such studies can be seen in the discovery of
RXCJ0600-z6, as upon observing it astronomers found that the galaxy was
rotating. Prior to this discovery it was believed that the gas in young
galaxies has random and chaotic movement patterns, but this galaxy, and
several others discovered by ALMA, have challenged this theory. Of the
galaxies which have contributed to this new research, RXCJ0600-z6 is the
smallest one.
The
discovery of RXCJ0600-z6 also looks promising when it comes to the
future of our study of the universe, according to DAWN fellow at the
Niels Bohr Institute, Seiji Fujimoto. Due to the high magnification
factor of the galaxy it will be possible to observe it through the James
Webb Space Telescope (JWST) in the coming months. The combination of
ALMA and JWST will allow astronomers to further understand the intricate
properties of gas and stars, and all of their internal motions inside
of the small galaxy. There is hope that in the future our technology
will advance to such a degree that even individual stars will be able to
be viewed using gravitational lensing.
Dr.
Adi Zitrin of the physics department at Ben-Gurion University shares
Fujimoto's optimism about our future understanding of the universe,
saying that "it is great to see the range of science enabled by
gravitational lensing in recent years. Lensing, paired with new and
advanced instruments that are being built, such as the James Webb Space
Telescope (JWST), will surely lead to more exciting and unprecedented
discoveries."
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