A baffling, distant galaxy has no signs of dark matter whatsoever

'This result does not fit in with the currently accepted cosmological models,' one of the scientists behind the discovery explained.
Chris Young
The dark matter-free galaxy NGC 1277.
The dark matter-free galaxy NGC 1277.

NASA / ESA / M. Beasley (IAC) 

An international team of astrophysicists led by the Instituto de Astrofísica de Canarias (IAC) and the University of La Laguna (ULL) found the first evidence of a massive galaxy with no dark matter.

The baffling discovery challenges the standard cosmology model and could help shed new light on the dark matter due to its conspicuous absence from the galaxy NGC 1277, a press statement reveals.

A galaxy with no dark matter

The researchers, who published their findings in the journal Astronomy and Astrophysics, found that the galaxy NGC 1277, which has several times the mass of the Milky Way, has a mass distribution indicating no dark matter.

Study lead Sebastién Comerón, from the IAC and ULL, explained that "this result does not fit in with the currently accepted cosmological models, which include dark matter."

In the existing standard model of cosmology, massive galaxies are primarily composed of dark matter. While dark matter has never been directly observed, it is inferred due to its observable gravitational pull on surrounding cosmic objects such as planets and stars.

NGC 1277 is an exceedingly rare example of a "relic galaxy", meaning it is far away enough to have had no interactions with its galactic neighbors. Relic galaxies are believed to be the remnants of giant galaxies that formed in the early universe.

"The importance of relic galaxies in helping us to understand how the first galaxies formed was the reason we decided to observe NGC 1277 with an integral field spectrograph" Comerón said. "From the spectra we made kinematic maps which enabled us to work out the distribution of mass within the galaxy out to a radius of some 20,000 light years."

Essentially, the team found that the total mass distribution of NGC 1277 was equivalent to only the distribution of the stars rather than the extra percentage of dark matter typically associated with a large galaxy.

The dark matter-free galaxy puzzle

According to today's cosmological models, a galaxy with the mass of NGC 1277 should have at least 10 percent of its mass in the form of dark matter and could have up to 70 percent.

In their paper, the scientists have posed hypotheses regarding NGC 1277, including that gravitational interaction with the surrounding medium within the galaxy cluster in which the galaxy is located may have removed its dark matter.

However, "the puzzle of how a massive galaxy can form without dark matter remains a puzzle," Comerón said. Next, the team will perform follow-up observations with the WEAVE instrument on the William Herschel Telescope (WHT) at the Roque de los Muchachos Observatory in the Canary Island of La Palma.

If they can confirm that NGC 1277 does not have dark matter, it could massively impact our understanding of the cosmos and challenge alternative models for dark matter that rely on the mysterious phenomenon being close to uniform throughout the universe.

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