A2261-BCG (short for Abell 2261

Brightest Cluster Galaxy A brightest cluster galaxy (BCG) is defined as the brightest galaxy in a cluster of galaxies. BCGs include the List of largest galaxies, most massive galaxies in the universe. They are generally elliptical galaxies which lie close to the geometr ...

) is a huge elliptical galaxy in the cluster

Abell 2261 Abell 2261 is one of 25 galaxy clusters being studied as part of the Cluster Lensing And Supernova survey with Hubble (CLASH) program, a major project to build a library of scientific data on lensing clusters. It also has the galaxy A2261-BCG ( ...

. One of the largest galaxies known, A2261-BCG is estimated to have a diameter of a million light-years, some 10 times larger than 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 ...

. It is the brightest and the most massive galaxy in the cluster, and has one of the largest galactic cores ever observed, spanning more than 10,000 light-years. Yet, unusually, its center does not contain a

supermassive black hole A supermassive black hole (SMBH or sometimes SBH) is the largest type of black hole, with its mass being on the order of hundreds of thousands, or millions to billions, of times the mass of the Sun (). Black holes are a class of astronomical ...

. The cD elliptical galaxy, located at least 3 billion light-years from Earth, is also well known as a radio source. Its core is highly populated by a dense number of old stars, but is mysteriously diffuse, giving it a large core. On September 10, 2012, using

Hubble Space Telescope The Hubble Space Telescope (HST or Hubble) is a space telescope that was launched into low Earth orbit in 1990 and remains in operation. It was not the Orbiting Solar Observatory, first space telescope, but it is one of the largest and most ...

's Wide Field Camera 3, scientists realized there was no

present in its center.

References

Elliptical galaxies Hercules (constellation) 1981854 {{Elliptical-galaxy-stub