Markarian Chain, Virgo Galaxy Cluster
The Markarian Chain of galaxies is part of the Virgo Cluster, a group of galaxies about 60 million light years
away centered in the constellation Virgo. There are about 1300, and possibly as many as 2000, galaxies in
this cluster. Galaxies are not distributed randomly in space, but rather form gravitationally bound clusters.
The Virgo Cluster forms the heart of the larger Local Supercluster of galaxies. Our galaxy, the Milky Way,
is part of the Local Group of galaxies and is an outlying member of the Supercluster. The large mass of the
Virgo Cluster has gravitational effects on our Local Group and is thought to be slowing its movement by
about ten percent.
Many of the member galaxies of the Virgo Cluster are visible with a small telescope and several of them are
Messier objects (e.g., M84, 86 and 87 shown in this image). The cluster is a fairly heterogeneous mixture
of spirals and ellipticals. It is believed that the spirals of the cluster are distributed in an elongated sphere
about 4 times as long as wide, stretching along the line of sight from the Milky Way. The elliptical galaxies in
the cluster are more centrally concentrated than the spiral galaxies. To give you an idea of scale, M87,
which is shown in the upper left corner of this image, is thought to be about 120,000 light years in
diameter. Our own galaxy, the Milky Way, is about 100,000 light years in diameter. However, since M87 is
an elliptical galaxy shaped like an egg rather than a disc, it has a much larger volume than the Milky Way
and thus many more stars. Some estimates claim over a trillion stars exist in M87.
The Markarian Chain got its name from Benjamin Markarian (1913-1985), a Russian astronomer, who
published a paper on this group of galaxies in 1961. In that paper he proposed that the chain was more
than a random arrangement of galaxies and that they formed a physical system. You can read the
Astronomical Journal article here. At the time, not everyone agreed with the validity of his hypothesis, but
his name is now associated with this beautiful grouping of galaxies.
Markarian worked most of his career at the Byurakan Astrophysical Observatory (BAO) in what is now the
Republic of Armenia. The observatory is located in a mountainous area near Mt. Aragatz (13,435 ft), the
highest point in Armenia. It was founded 1946 and fell on hard times after the disintegration of the Soviet
Union. In 1953 Markarian was appointed the acting director of the observatory. He is remembered as
being a strict, but fair director. He resigned that post in 1956 to return to research. In addition to his work
on the Markarian Chain, he is best known for his work on galaxies exhibiting “excessive UV radiation.”
Markarian and is colleagues at the Byurakan Observatory also published two important spectral surveys of
galaxies (First and Second Byurakan Spectral Surveys of the Northern Sky). According to an on-line
biography “till the end of his life, in spite of his bad health, Markarian worked actively, continuing to do the
main job of his scientific activity, survey works on extragalactic astronomy."
away centered in the constellation Virgo. There are about 1300, and possibly as many as 2000, galaxies in
this cluster. Galaxies are not distributed randomly in space, but rather form gravitationally bound clusters.
The Virgo Cluster forms the heart of the larger Local Supercluster of galaxies. Our galaxy, the Milky Way,
is part of the Local Group of galaxies and is an outlying member of the Supercluster. The large mass of the
Virgo Cluster has gravitational effects on our Local Group and is thought to be slowing its movement by
about ten percent.
Many of the member galaxies of the Virgo Cluster are visible with a small telescope and several of them are
Messier objects (e.g., M84, 86 and 87 shown in this image). The cluster is a fairly heterogeneous mixture
of spirals and ellipticals. It is believed that the spirals of the cluster are distributed in an elongated sphere
about 4 times as long as wide, stretching along the line of sight from the Milky Way. The elliptical galaxies in
the cluster are more centrally concentrated than the spiral galaxies. To give you an idea of scale, M87,
which is shown in the upper left corner of this image, is thought to be about 120,000 light years in
diameter. Our own galaxy, the Milky Way, is about 100,000 light years in diameter. However, since M87 is
an elliptical galaxy shaped like an egg rather than a disc, it has a much larger volume than the Milky Way
and thus many more stars. Some estimates claim over a trillion stars exist in M87.
The Markarian Chain got its name from Benjamin Markarian (1913-1985), a Russian astronomer, who
published a paper on this group of galaxies in 1961. In that paper he proposed that the chain was more
than a random arrangement of galaxies and that they formed a physical system. You can read the
Astronomical Journal article here. At the time, not everyone agreed with the validity of his hypothesis, but
his name is now associated with this beautiful grouping of galaxies.
Markarian worked most of his career at the Byurakan Astrophysical Observatory (BAO) in what is now the
Republic of Armenia. The observatory is located in a mountainous area near Mt. Aragatz (13,435 ft), the
highest point in Armenia. It was founded 1946 and fell on hard times after the disintegration of the Soviet
Union. In 1953 Markarian was appointed the acting director of the observatory. He is remembered as
being a strict, but fair director. He resigned that post in 1956 to return to research. In addition to his work
on the Markarian Chain, he is best known for his work on galaxies exhibiting “excessive UV radiation.”
Markarian and is colleagues at the Byurakan Observatory also published two important spectral surveys of
galaxies (First and Second Byurakan Spectral Surveys of the Northern Sky). According to an on-line
biography “till the end of his life, in spite of his bad health, Markarian worked actively, continuing to do the
main job of his scientific activity, survey works on extragalactic astronomy."
| Part of the Byurakan Observatory with Mt. Aragatz in the backgound (from BAO website). |
| Benjamin Markarian (from BAO website) |
| The Markarian Chain, plus M87 (above left). Click on image for a large size image. Click on the second image for full-size. Mosaic of two images, 10 x 10 minutes each. TAK 106ED, ST10XME, external guiding Borg 77ED, SBIG Remote Guider |
| The Markarian Chain with major galaxies labeled. Faint galaxies are indicated with an arrow only. Almost 50 galaxies can be seen in this image. |
