Gemini Images Galaxy That Is 99.99 Percent Dark Matter

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The low universe Dragonfly 44. The picture on a left is a far-reaching perspective of a universe taken with a Gemini North telescope regulating a Gemini Multi-Object Spectrograph (GMOS) as partial of a Fast Turnaround program. The close-up on a right is from a same unequivocally low image, divulgence a large, elongated galaxy, and halo of round clusters of stars around a galaxy’s core, identical to a halo that surrounds a Milky Way Galaxy. Dragonfly 44 is unequivocally gloomy for a mass, and consists roughly wholly of Dark Matter. Image Credit: Pieter outpost Dokkum, Roberto Abraham, Gemini Observatory/AURA.

The low universe Dragonfly 44. The picture on a left is a far-reaching perspective of a universe taken with a Gemini North telescope regulating a Gemini Multi-Object Spectrograph (GMOS) as partial of a Fast Turnaround program. The close-up on a right is from a same unequivocally low image, divulgence a large, elongated galaxy, and halo of round clusters of stars around a galaxy’s core, identical to a halo that surrounds a Milky Way Galaxy. Dragonfly 44 is unequivocally gloomy for a mass, and consists roughly wholly of Dark Matter. Image Credit: Pieter outpost Dokkum, Roberto Abraham, Gemini Observatory/AURA.

Using a world’s many absolute telescopes, an general group of astronomers has detected a vast universe that consists roughly wholly of Dark Matter. Using a W. M. Keck Observatory and a Gemini North telescope – both on Maunakea, Hawai‘i – a group found a universe whose mass is roughly wholly Dark Matter. The commentary are being published in The Astrophysical Journal.

Even yet it is comparatively nearby, astronomers had missed a galaxy, named Dragonfly 44, for decades since it is unequivocally dim. It was detected usually final year when a Dragonfly Telephoto Array celebrated a segment of a sky in a constellation Coma. Upon serve scrutiny, a group satisfied a universe had to have some-more than meets a eye: it has so few stars that it quick would be ripped detached unless something was holding it together.

To establish a volume of Dark Matter in Dragonfly 44, astronomers used a DEIMOS spectrograph commissioned on Keck II to magnitude a velocities of stars for 33.5 hours over a duration of 6 nights so they could establish a galaxy’s mass. The group afterwards used a Gemini Multi-Object Spectrograph (GMOS) on a 8-meter Gemini North telescope on Maunakea in Hawai‘i to picture a universe and a halo of round clusters of stars around a galaxy’s core, identical to a halo that surrounds a Milky Way Galaxy (full-resolution picture is accessible during a couple supposing above).

“Motions of a stars tell we how most matter there is,” outpost Dokkum said. “They don’t caring what form a matter is, they usually tell we that it’s there. In a Dragonfly universe stars pierce unequivocally fast. So there was a outrageous discrepancy: regulating Keck Observatory, we found many times some-more mass indicated by a motions of a stars, afterwards there is mass in a stars themselves.”

The mass of a universe is estimated to be a trillion times a mass of a Sun – unequivocally identical to a mass of a possess Milky Way galaxy. However, usually one hundredth of one percent of that is in a form of stars and “normal” matter; a other 99.99 percent is in a form of Dark Matter. The Milky Way has some-more than a hundred times some-more stars than Dragonfly 44.

Finding a universe with a mass of a Milky Way that is roughly wholly low was unexpected. “We have no thought how galaxies like Dragonfly 44 could have formed,” Roberto Abraham, a co-author of a investigate from a University of Toronto, said. “The Gemini information uncover that a comparatively vast fragment of a stars are in a form of unequivocally compress clusters, and that is substantially an critical clue. But during a impulse we’re usually guessing.”

“This has large implications for a investigate of Dark Matter,” outpost Dokkum said. “It helps to have objects that are roughly wholly done of Dark Matter so we don’t get confused by stars and all a other things that galaxies have. The usually such galaxies we had to investigate before were tiny. This anticipating opens adult a whole new category of vast objects that we can study.

“Ultimately what we unequivocally wish to learn is what Dark Matter is,” outpost Dokkum said. “The competition is on to find vast low galaxies that are even closer to us than Dragonfly 44, so we can demeanour for handicapped signals that might exhibit a Dark Matter particle.”

Source: Gemini