Hubble telescope discovers galaxy with no dark matter


Given the object's large size and faint appearance, astronomers classify NGC 1052-DF2 as an ultra-diffuse galaxy.

A galaxy far, far away is perplexing astronomers not because of what it contains, but because of what it doesn't: dark matter.

"For decades, we thought that galaxies started life as dark matter patches, after which everything happens: the gas falls into these halos of dark matter, turning into stars".

Van Dokkum plans to use Keck to search for more galaxies like NGC 1052-DF2. "It's so rare, particularly these days after so many years of Hubble, that you get an image of something and say, 'I've never seen that before'".

Van Dokkum and his colleagues used the Dragonfly Telephoto Array to track the motion of 10 known star clusters to determine how massive the galaxy is. To understand more, Roberto Abraham and Pieter van Dokkum, armed with their awesome telescope, are already looking for other similar galaxies.

The galaxy had been imaged before but on second look, the team noticed it looked very different from other imaged galaxies. The team determined nearly all of the galaxy's mass could be attributed to stars, which means there is nearly no dark matter, the release said. It's so sparse that you see all of the galaxies behind it.

Before, scientists believed that galaxies were composed of stars, gases and dark matter, all mixed together.

Also, it is generally accepted that galaxies first formed from concentrations of dark matter that act like "galaxy starters".

He also raised the possibility that another galaxy nearby was tweaking NGC 1052-DF2's motion through an element of MOND called the "external field effect".

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The authors of the research on this ghostly galaxy were initially looking out for a galaxy which is dark matter free; instead, they looked into ultra-diffuse galaxies.

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.

And, yet, scientists using telescopes atop Maunakea found one galaxy that has nearly none at all. The formation of NGC 1052-DF2 may have been helped by powerful winds emanating from the young black hole that was growing in the center of NGC 1052.

This might seem counterintuitive, but DF2 actually supports the existence of dark matter, which some theories argue doesn't exist. It moves just as fast as the regular old laws of astrophysics would suggest, when calculated based on the mass of the stars researchers can see.

Lying some 63 million light-years from the Milky Way, the elliptical galaxy NGC1052-DF2 seems to be completely made up of normal matter, defying all expectations. But how it formed is a complete mystery. This would allow the gas to form stars away from clumps of dark matter. This is only expected if dark matter is bound to ordinary matter through nothing but gravity. Already have suspicions of three, whom they will notice better.

We don't really know what dark matter is and why it exists... or why it doesn't. The paper appears in the March 29 issue of the journal Nature.

More work has to be done by the team which is conducting this research and after that, the actual occurrence of the galaxy and the non-occurrence of the dark matter will be proved.

NGC 1052-DF2 is missing its dark matter.

Bottom line: The galaxy NGC 1052-DF2 appears to have no dark matter. Future observatories under construction, such as the European Extremely Large Telescope in Chile's Atacama Desert, or NASA's James Webb Space Telescope, should be able to take such measurements.