Astronomers discover Vela, a major supercluster of galaxies lying behind the Milky Way


As part of a new research, scientists have stumbled upon a hitherto-unknown major supercluster in the Vela constellation. Currently being called the Vela supercluster, this massive concentration of galaxies comes with a large gravitational force that, astronomers believe, might have a substantial effect on the motion of the 54 galaxies in the Local Group, including the Milky Way. Additionally, it could play a role in the peculiar velocity of our Local Group with respect to the Cosmic Microwave Background.

Superclusters have long held the interest of researchers, being as they are the largest and most enormous objects in the entire universe. These structures extend over a total distance of 200 million light-years, with the most famous one being the Shapley Supercluster. Situated approximately 65 million light-years away, it is the largest of its kind in our cosmic neighborhood.

Recently, however,  an international team of scientists has discovered an equally massive supercluster lying in the vicinity of Shapley (around 800 million light-years away). The research, conducted by astronomers from Germany, Australia, South Africa, Netherlands as well as two from the  Max-Planck-Institut für extraterrestrische Physik in Garching, is the first to reveal the existence of the Vela supercluster, which appears to take up an even larger area in the sky than its more famous counterpart.

The structure likely escaped notice for so long, thanks to its location behind the galactic plane of the Milky Way. The region is further made obscure by dust and smaller stars. Believed to be at least as big as the Shapley, the Vela supercluster could possibly have an influence on the movements of nearby celestial bodies. According to the researchers, it was discovered via multi-object spectroscopic observations of several thousand partially-obscured galaxies.

Back in 2012, the team confirmed the existence of eight giant clusters within the Vela region, using the spectrograph at the Southern Africa Large Telescope (or SALT). Based on the observation of numerous galaxy redshifts, made with the help of the Anglo-Australian Telescope, the astronomers were able to estimate the size of the massive structure. Speaking about the findings, which was recently published in the Monthly Notices Letters of the Royal Astronomical Society, Renée Kraan-Korteweg, a professor at the University of Cape Town and the study’s leader, said:

I could not believe such a major structure would pop up so prominently.

The findings were confirmed by scientists Gayoung Chon and Hans Böhringer of Garching-based Max-Planck-Institut für extraterrestrische Physik, who looked for X-Ray luminous galaxy clusters in the area uncovered by the redshift survey. During their examination, the duo came across several major clusters in and around the region. They added:

This discovery shows that the Vela supercluster has a significantly higher matter density than average, making it a prominent large structure… We already have good indications that the Vela Supercluster is embedded in a large network of cosmic filaments traced by clusters, providing insight into the even larger-scale structure embedding the Vela Supercluster. With the future multi-wavelength programme we hope to unveil its full influence on the cosmography and cosmology.

Despite the impressive discovery, the scientists have before them the arduous task of determining the mass, exact location as well as influence of the newly-discovered Vela supercluster on the various objects of the Local Group.

Source: Max Planck Institute for Extraterrestrial Physics

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