Published: Fri, March 30, 2018
Science | By

A galaxy without dark matter

A galaxy without dark matter

In fact, the research team had previously looked at galaxies of the same class as NGC1052-DF2 and found they were made up nearly entirely of dark matter. But upon further study, an global team of astronomers was surprised to discover that it had no dark matter, something that has been seen as crucial in the formation of galaxies.

The researchers seemingly anticipate the sorts of questions that will be posed by people who see this and wonder why we need any dark matter around anyway (a population that includes a number of regular Ars readers).

Adding up the clusters' motions and NGC 1052-DF2's mass, they realized there might be no dark matter behind this particular galactic curtain.

This is weird-and it could change what astrophysicists think dark matter is, in addition to upending their understanding of how galaxies form, says van Dokkum.

Scientists have discovered a galaxy with nearly no dark matter. Now, however, researchers have found a galaxy that seems to have no dark matter at all.

Roberto Abraham, left, Pieter van Dokkum, right, and their team of University of Toronto and Yale University graduate students pose with one-half of the 48-lens Dragonfly array at its home site in New Mexico.

There have been several ideas that have floated around regarding the true nature of dark matter, and discoveries like this will only push astronomers to unlocking its secrets.

DF2, being located in a cluster dominated by a giant elliptical galaxy, NGC 1052, is perhaps under the influence of the latter. Scientists have found that normal matter - the stuff we do see - makes up only around 15 per cent of all the matter in the universe.

"It is conventionally believed to be an integral part of all galaxies, the glue that holds them together and the underlying scaffolding on which they are built", said co-author Allison Merritt from the Max Planck Institute for Astronomy, in Germany.

Closer monitorings utilizing the Hubble and also 10-meter Keck telescopes revealed that the item, now described NGC1052- DF2, belonged to a lately uncovered course of things called ultra-diffuse galaxies. "It's like you take a galaxy and also you just have the excellent halo and also globular collections, as well as it in some way neglected to earn whatever else", kept in mind van Dokkum.

The galaxy had been imaged before but on second look, the team noticed it looked very different from other imaged galaxies. Using the amount of light emitted by the galaxy produced an estimate of the total mass of stars in the galaxy that was also in the neighborhood of 10. Their measurements showed that this galaxy's stars can handle its rotational speed. For example, they can look at how fast stars cruise around a galaxy. A Yale-led research team made the discovery while peering at the distant galaxy NGC 1052-DF2. But the dark matter floated in clumps.

If there is any dark matter at all, it's very little. "It's so sparse that you can see all the galaxies behind it". What's more, shockingly, it's about a similar measure of mass they'd hope to see from the galaxy's stars. It could be that NGC 1052-DF2 was once a placid mass of gas and has been recently perturbed by another unseen galaxy nearby, sparking star formation. But dark matter was the majority.

Scientists have various theories on how this galaxy came to be. "It is completely unknown how it is possible to form such a galaxy". The leading dark matter theory predicts that this "sea" of particles moves around a galaxy in deep, plunging orbits like comets around the sun.

Astronomers will be looking to find other galaxies in the universe. NASA's Goddard Space Flight Center in Greenbelt, Maryland, manages the telescope.

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