Abell
50.2218
The picture shows Abell 2218, a rich galaxy cluster composed of thousands of
individual galaxies. It sits about 2.1 billion light-years from the Earth (redshift 0.17)
in the northern constellation of Draco. When used by astronomers as a powerful
gravitational lens to magnify distant galaxies, the cluster allows them to peer far into
the Universe. However, it not only magnifies the images of hidden galaxies, but also
distorts them into long, thin arcs.
Several arcs in the image can be studied in detail thanks to Hubble’s sharp vision.
Multiple distorted images of the same galaxies can be identified by comparing the
shape of the galaxies and their colour. In addition to the giant arcs, many smaller
arclets have been identified.
Credit: NASA, ESA, and Johan Richard (Caltech, USA)
“I’m a co-investigator on 3D-HST*, a spectroscopic
Hubble Treasury Program, mapping the
third dimension of distance for thousands of
galaxies across 85% of cosmic time. Together
with another large imaging Treasury Program,
CANDELS, these projects serve as the premier
extragalactic surveys in the sky. With thousands of
orbits invested by the Hubble Space Telescope,
as well as at other wavelengths across the
electromagnetic spectrum, CANDELS and 3D-HST
have revolutionized our understanding of galaxy
formation.
“I’ve also been involved with studying the strong
gravitationally-lensed actively star-forming galaxy
RCS0327. Gravitational lensing affords us the
opportunity to see significantly more details than
could ever be achieved for unlensed galaxies.
RCS0327 serves as a unique laboratory to study the
physical properties of a galaxy existing at the peak
of cosmic star formation, only a few billion years
after the Big Bang.”
— Dr. Katherine E. Whitaker
NASA Postdoctoral Program Fellow
Goddard Space Flight Center
Greenbelt, Maryland
* http://hubblesite.org/newscenter/archive/releases/2013/45/full/