Annotated image of the field around CLASS B1608+656
Digitized Sky Survey Image around CLASS B1608+656
(ground-based image)
******************
Videos
An image of a galaxy cluster taken by the
NASA/ESA Hubble Space Telescope gives a remarkable cross-section of the
Universe, showing objects at different distances and stages in cosmic
history. They range from cosmic near neighbours to objects seen in the
early years of the Universe. The 14-hour exposure shows objects around a
billion times fainter than can be seen with the naked eye.
This new Hubble image showcases a remarkable variety of objects at
different distances from us, extending back over halfway to the edge of
the observable Universe. The galaxies in this image mostly
lie about five billion light-years from Earth but the field also
contains other objects, both significantly closer and far more distant.
Studies of this region of the sky have shown that many of the objects
that appear to lie close together may actually be billions of
light-years apart. This is because several groups of galaxies lie along
our line of sight, creating something of an optical illusion. Hubble’s
cross-section of the Universe is completed by distorted images of
galaxies in the very distant background.
These objects are sometimes distorted due to a process called
gravitational lensing, an extremely valuable technique in astronomy for
studying very distant objects [1].
This lensing is caused by the bending of the space-time continuum by
massive galaxies lying close to our line of sight to distant objects.
One of the lens systems visible here is called CLASS B1608+656, which
appears as a small loop in the centre of the image. It features two
foreground galaxies distorting and amplifying the light of a distant
quasar the known as QSO-160913+653228. The
light from this bright disc of matter, which is currently falling into a
black hole, has taken nine billion years to reach us — two thirds of
the age of the Universe.
As well as CLASS B1608+656, astronomers have identified two other
gravitational lenses within this image. Two galaxies, dubbed Fred and
Ginger by the researchers who studied them, contain enough mass to
visibly distort the light from objects behind them. Fred, also known
more prosaically as [FMK2006] ACS J160919+6532, lies near the lens
galaxies in CLASS B1608+656, while Ginger ([FMK2006] ACS J160910+6532)
is markedly closer to us. Despite their different distances from us,
both can be seen near to CLASS B1608+656 in the central region of this
Hubble image.
To capture distant and dim objects like these, Hubble required a long
exposure. The image is made up of visible and infrared observations
with a total exposure time of 14 hours.
Notes
[1] Gravitational lensing can amplify
the light coming from distant objects, enabling telescopes like Hubble
to see objects that would otherwise be too faint and far away. This
effect will be exploited during the Frontier Fields
observing campaign in the near future, which aims to combine the power
of Hubble with the natural amplification caused by strong gravitational
lensing of distant galaxy clusters, to study the past Universe.
More information
The Hubble Space Telescope is a project of international cooperation between ESA and NASA.
The image was spotted by contestant Adam Kill in the 2012 Hubble's
Hidden Treasures competition. Hidden Treasures invited members of the
public to search Hubble's science for the best overlooked images that
have never been seen by a general audience. This image of CLASS
B1608+656 has been well-studied by scientists over the years, but this
is the first time it has been published in full online.
Links
Contacts
Georgia BladonHubble/ESA
Garching, Germany
Tel: +49-89-3200-6855
Email: gbladon@partner.eso.org
