Abell 370 parallel field
Digitized sky survey image of Abell 370 (ground-based image)
Abell 370 (seen in 2009)
Videos
The Hubble Space Telescope is a project of international cooperation between ESA and NASA.
Mathias Jäger
Zoom-in on Abell 370
Image Comparisons
Comparison of Abell 370 in 2009 and 2016
The NASA/ESA Hubble Telescope has peered
across six billion light years of space to resolve extremely faint
features of the galaxy cluster Abell 370 that have not been seen before.
Imaged here in stunning detail, Abell 370 is part of the Frontier
Fields programme which uses massive galaxy clusters to study the
mysteries of dark matter and the very early Universe.
Six billion light-years away in the constellation Cetus (the Sea Monster), Abell 370 is made up of hundreds of galaxies [1].
Already in the mid-1980s higher-resolution images of the cluster showed
that the giant luminous arc in the lower left of the image was not a
curious structure within the cluster, but rather an astrophysical
phenomenon: the gravitationally lensed
image of a galaxy twice as far away as the cluster itself. Hubble
helped show that this arc is composed of two distorted images of an
ordinary spiral galaxy that just happens to lie behind the cluster.
Abell 370’s enormous gravitational influence warps the shape of
spacetime around it, causing the light of background galaxies to spread
out along multiple paths and appear both distorted and magnified. The
effect can be seen as a series of streaks and arcs curving around the
centre of the image. Massive galaxy clusters
can therefore act like natural telescopes, giving astronomers a
close-up view of the very distant galaxies behind the cluster — a
glimpse of the Universe in its infancy, only a few hundred million years
after the Big Bang.
This image of Abell 370 was captured as part of the Frontier Fields
programme, which used a whopping 630 hours of Hubble observing time,
over 560 orbits of the Earth. Six clusters of galaxies were imaged in
exquisite detail, including Abell 370 which was the very last one to be
finished. An earlier image of this object — using less observation time
and therefore not recording such faint detail — was published in 2009.
During the cluster observations, Hubble also looked at six “parallel
fields”, regions near the galaxy clusters which were imaged with the
same exposure times as the clusters themselves. Each cluster and
parallel field were imaged in infrared light by the Wide Field Camera 3 (WFC3), and in visible light by the Advanced Camera for Surveys (ACS).
The Frontier Fields programme produced the deepest observations ever
made of galaxy clusters and the magnified galaxies behind them. These
observations are helping astronomers understand how stars and galaxies
emerged out of the dark ages of the Universe, when space was dark, opaque, and filled with hydrogen.
Studying massive galaxy clusters like Abell 370 also helps with measuring the distribution of normal matter and dark matter within such clusters [heic1506].
By studying its lensing properties, astronomers have determined that
Abell 370 contains two large, separate clumps of dark matter,
contributing to the evidence that this massive galaxy cluster is
actually the result of two smaller clusters merging together.
Now that the observations for the Frontier Fields programme are
complete, astronomers can use the full dataset to explore the clusters,
their gravitational lensing effects and the magnified galaxies from the
early Universe in full detail.
Notes
[1] Galaxy clusters are the most massive structures in the Universe that
are held together by gravity, generally thought to have formed when
smaller groups of galaxies smashed into each other in ever-bigger cosmic
collisions. Such clusters can contain up to 1000 galaxies, along with
hot intergalactic gas that often shines brightly at X-ray wavelengths,
all bound together primarily by the gravity of dark matter.
More Information
The Hubble Space Telescope is a project of international cooperation between ESA and NASA.
Image credit: NASA, ESA, HST Frontier Fields
Links
Contacts
Mathias Jäger
ESA/Hubble, Public Information Officer
Garching bei München, Germany
Tel: +49 176 6239750
Email: mjaeger@partner.eso.org
Source: ESO/Hubble/News
