Vela Supercluster: Larger and More Massive Than Previously Understood

Astronomers have determined the true extent of the Vela Supercluster, revealing it to be larger and more massive than previously understood. This discovery, made by scientists at the University of Cape Town (UCT) and an international team, offers insights into one of the largest structures in the nearby universe and helps explain large-scale galaxy movements.

The enormous concentration of galaxies in the Vela Supercluster had been largely obscured by dust clouds and stars within the Milky Way's disk, a region termed the "Zone of Avoidance."

Unveiling the Hidden Giant

The research team employed a hybrid technique combining multiple types of galaxy measurements, including galaxy redshifts, which indicate how fast galaxies move away due to universal expansion, and measurements of galaxy distance and motion influenced by gravity.

Over 65,000 galaxy distance measurements from the CosmicFlows catalogue were combined with more than 8,000 new galaxy redshifts. Observations from the Southern African Large Telescope and the MeerKAT radio telescope were crucial, with MeerKAT's radio observations detecting hydrogen gas through dust, allowing visibility of otherwise obscured galaxies.

Key Revelations About Vela-Banzi

• The Vela Supercluster is located approximately 800 million light-years away.
• It spans about 300 million light-years.
• Its estimated mass is equivalent to about 30 million billion suns, comparable to the Shapley Supercluster.
• The system includes two dense cores moving towards each other.
• Its gravitational influence may surpass that of other major structures such as the Laniakea Supercluster (which contains our galaxy) and the Great Attractor.

Cosmic Impact and Naming

Renee Kraan-Korteweg, an emeritus professor at UCT's Department of Astronomy, stated that the findings confirmed suspicions held for over a decade regarding the prominence and role of the Vela-Banzi supercluster in cosmic flows, including those affecting our Local Group of galaxies.

Former UCT doctoral student Sambatriniaina Rajohnson noted that the discovery helps complete the map of the nearby universe, revealing a major gravitational influence previously hidden.

The team has proposed the name "Vela-Banzi" for the structure, deriving "Banzi" from the Xhosa language, meaning "revealing widely," to reflect its emergence as one of the largest known structures in the nearby cosmos.