Abell 370
Encyclopedia
Abell 370 is a galaxy cluster
located approximately 6 billion light years away from the Earth (at redshift z=0.375), in the constellation Cetus
. Its core is made up of several hundred galaxies. It was catalogued by George Abell
, and is the most distant of the clusters he catalogued.
s caused by gravitational lensing of more distant objects.
In 2002, astronomers used this lensing effect to discover a galaxy, HCM-6A
, 12.8 billion light years away from Earth. At the time it was the furthest known galaxy.
In 2009, study in the field of Abell 370 revealed a grouping of background galaxies lensed and distorted by the cluster into an arc with the appearance of a dragon, hence nicknamed The Dragon by NASA scientists. Its head is composed of a spiral galaxy, with another spiral composing the tail. Several other galaxies form the body of the dragon, all overlapping. These galaxies all lie approximately 10 billion light years away.
Galaxy cluster
A galaxy cluster is a compact cluster of galaxies. Basic difference between a galaxy group and a galaxy cluster is that there are many more galaxies in a cluster than in a group. Also, galaxies in a cluster are more compact and have higher velocity dispersion. One of the key features of cluster is...
located approximately 6 billion light years away from the Earth (at redshift z=0.375), in the constellation Cetus
Cetus
Cetus is a constellation. Its name refers to Cetus, a sea monster in Greek mythology, although it is often called 'the whale' today. Cetus is located in the region of the sky that contains other water-related constellations such as Aquarius, Pisces, and Eridanus.-Ecliptic:Although Cetus is not...
. Its core is made up of several hundred galaxies. It was catalogued by George Abell
George Ogden Abell
George Ogden Abell was an astronomer at UCLA. He worked as a research astronomer, teacher, administrator, popularizer of science and education, and skeptic. Abell received his B.S. , M.S. and Ph.D. from the California Institute of Technology...
, and is the most distant of the clusters he catalogued.
Gravitational lensing
Abell 370 appears to include several arcs of light, which in fact are mirageMirage
A mirage is a naturally occurring optical phenomenon in which light rays are bent to produce a displaced image of distant objects or the sky. The word comes to English via the French mirage, from the Latin mirare, meaning "to look at, to wonder at"...
s caused by gravitational lensing of more distant objects.
In 2002, astronomers used this lensing effect to discover a galaxy, HCM-6A
HCM-6A
HCM-6A is a galaxy that was found in 2002 by a team led by Esther Hu from the University of Hawaii, using the Keck II Telescope in Hawaii. HCM-6A is located behind the Abell 370 galactic cluster, near M77 in the constellation Cetus, which enabled the astronomers to use Abell 370 as a gravitational...
, 12.8 billion light years away from Earth. At the time it was the furthest known galaxy.
In 2009, study in the field of Abell 370 revealed a grouping of background galaxies lensed and distorted by the cluster into an arc with the appearance of a dragon, hence nicknamed The Dragon by NASA scientists. Its head is composed of a spiral galaxy, with another spiral composing the tail. Several other galaxies form the body of the dragon, all overlapping. These galaxies all lie approximately 10 billion light years away.