According to lead author Pieter van Dokkum, dark matter has always been considered the most dominant aspect of a galaxy. "We thought for decades that galaxies begin their lives as dark matter," he explained. "Then everything else happens: gas falls into the halos of dark matter, the gas becomes stars, they slowly build up, and then you end up with galaxies like the Milky Way." The search for the galaxy with dark matter, named NGC1052-DF2, challenges the standard notions of how we form galaxies. "
The team made the discovery using a range of devices, including custom-made telescopes and spectrograph objects, and detailed images of NGC1
052-DF2 showed no signs of interacting with other galaxies, but did show a collection of relatively bright point-like sources These clusters are large, compact groups of stars orbiting the galactic nucleus, and spectral data showed that these clusters moved much slower than one would expect in a galaxy, as a rule of thumb: the slower the Move objects, the less mass there is in this system, and the team's calculations showed that the total mass in the galaxy could be assigned to the mass of these stars, which means that there is almost no dark matter in NGC1052-DF2. 19659002] The team is not sure how this weird galaxy came to be. "There is no theory that this Types of galaxies predicted, "van Dokkum said. "The galaxy is a complete mystery because it's all weird about it, how you actually do one of these things is completely unknown." However, there are some speculative theories. One suggestion is that one type of cataclysmic event swept away all gas and dark matter and stopped star formation. Another reason is that the formation of NGC1052-DF2 was somehow affected by the formation of another dominant nearby galaxy.
The team is now looking for other dark matter-deficient galaxies months. But NGC1052-DF2 surprised the scientists anyway. "Every galaxy we know before has dark matter, and all fall into familiar categories like spiral or elliptical galaxies," van Dokkum said. "But what would you get if there was no dark matter at all, maybe you would get that."