Alcyoneus Galaxy

Located around 3 billion light-years away in the Lynx constellation, is a radio galaxy which is named Alcyoneus Galaxy. This galaxy was discovered using the Wide-field Infrared Survey Explorer (WISE) telescope and the Low-Frequency Array (LOFAR) network and it is the largest discovered galaxy in the universe,


Currently, it is the largest galaxy discovered, with a width of around 5 million parsecs (16.3 million light-years). It is the largest known structure created by a single galaxy. A supermassive black hole weighing 400200 million solar masses has also been found in the host galaxy, SDSS J081421.68+522410.

Apart from the size, this galaxy is ordinary. The nearest cluster is 11 million light-years away, therefore it appears to be a stand-alone galaxy. It has been named Alcyoneus who was one of Heracles’ opponents according to Greek mythology.

How did Alcyoneus Galaxy become so massive?

It is unknown how Alcyoneus became so massive. Some theories that have been suggested are that it is less dense compared to its environmental surroundings and it also lies inside a supermassive black hole, a filament of the cosmic web, powerful jet streams, and an extensive stellar population.

The black hole which is present in the center of this galaxy is around 400 million times the sun’s mass.


LOFAR or the Low-Frequency Array is a large radio telescope network which is located in the Netherlands mainly. It was completed in the year 2012 by ASTRON, the Netherlands Institute for Radio Astronomy, along with international partners. LOFAR is operated by the radio observatory of ASTRON.

About Wide-field Infrared Survey Explorer (WISE)

It is a NASA Explorer program’s infrared astronomy satellite telescope. WISE was launched in the year 2009, and put into hibernation mode in 2011, before being reactivated in 2013 and renamed the Near-Earth Object Wide-field Infrared Survey Explorer (NEOWISE). Thousands of small planets and several star clusters were identified by WISE.



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