Dark globular cluster is a proposed type of
globular star clusters that has an unusually high mass for the number of stars within it. Proposed in 2015 on the basis of observational data, dark globular clusters are believed to be populated by objects with significant
dark matter
In astronomy, dark matter is an invisible and hypothetical form of matter that does not interact with light or other electromagnetic radiation. Dark matter is implied by gravity, gravitational effects that cannot be explained by general relat ...
components, such as central massive
black holes
A black hole is a massive, compact astronomical object so dense that its gravity prevents anything from escaping, even light. Albert Einstein's theory of general relativity predicts that a sufficiently compact mass will form a black hole. Th ...
.
Observational data
The observational data for dark globular clusters comes from the
Very Large Telescope
The Very Large Telescope (VLT) is an astronomical facility operated since 1998 by the European Southern Observatory, located on Cerro Paranal in the Atacama Desert of northern Chile. It consists of four individual telescopes, each equipped with ...
(VLT) in Chile which observed the vicinity of the galaxy
Centaurus A
Centaurus A (also known as NGC 5128 or Caldwell 77) is a galaxy in the constellation of Centaurus. It was discovered in 1826 by Scottish astronomer James Dunlop from his home in Parramatta, in New South Wales, Australia. There is considerable ...
.
Many of the globular clusters inside that galaxy are brighter and more massive than those orbiting the
Milky Way
The Milky Way or Milky Way Galaxy is the galaxy that includes the Solar System, with the name describing the #Appearance, galaxy's appearance from Earth: a hazy band of light seen in the night sky formed from stars in other arms of the galax ...
and a sample of 125 globular clusters around Centaurus A was studied using the VLT's FLAMES instrument.
While globular clusters are normally considered to be almost devoid of dark matter,
the study of the dynamical properties of sampled clusters suggested the presence of exotically concentrated dark matter.
[ The existence of dark globular clusters would suggest that their formation and evolution are markedly different from other globular clusters in Centaurus A and the ]Local Group
The Local Group is the galaxy group that includes the Milky Way, where Earth is located. It has a total diameter of roughly , and a total mass of the order of .
It consists of two collections of galaxies in a " dumbbell" shape; the Milky Way ...
.[
]
See also
References
{{Portal bar, Astronomy, Stars, Outer space
Globular clusters
Star clusters
Dark matter
Dark concepts in astrophysics