The Gaia satellite of the European Space Agency discovered a ghost galax tricking around the Milky Way.
An international team of astronomers discovered the object as described by the University of Cambridge as "huge" and "massive" – while screening data from the space observatory.
Double Antlia 2 (or Ant 2), the low density dverggal galaxy disappeared earlier detection by hiding behind the Milky Way disc, according to the researchers, whose results were published online last week.
Like other dwarf satellites, ant 2 probably arose in the early universe, consisting of millions to billions of old, low-mass and metallic stars.
However, contrary to Magellanic Clouds (or, frankly, any other known dwarf axle), Ant 2 is huge – one third of the size of the Roadmeter – and produces relatively little light.
"This is a ghost of a galaxy," says lead student writer Gabriel Torrealba, astronomer at the University of Cambridge, in a statement. "Items that diffuse like Ant 2 simply have not seen before. Our detection was only possible thanks to the quality of Gaia data."
ESA Observatory, designed to calculate positions and distance of stars, aims to construct the largest and more accurate 3D space catalog ever. So far, it has collected measurements of almost 1.7 billion stars.
Earlier this year, a second Gaia data pump made new information about stars in Winter Street available to researchers around the world. Among them, researchers from Australia, Germany, Taiwan, Great Britain and the United States, who used RR Lyrae stars to search for Milky Way satellites.
"RR Lyrae had been found in all known dwarf satellites, so when we found a group of those sitting above the Galactic disc, we were not completely surprised," co-author Vasily Belokurov, of the Cambridges Institute of Astronomy, said.
"But," he continued. "Looking closer to their location in the sky, we showed that we found something new, as no previously identified object appeared in any of the databases we searched."
The work quickly measured the team spectra of more than 100 red giant stars – just before the earth's orbit around the sun, Ant 2 made it memorable for several months.
Despite collecting more information, researchers continue to stumble off the strange galaxy.
With a mass much lower than expected for an object of its size, ant 2 is likely to be broken by Milk's Galactic Tidal. Which according to the convention would cause the system to shrink, not grow.
The best explanation, according to the astronomers, is that Antlia 2 was simply born enormously. Or it can be inflated by powerful star formation-star winds and supernova explosions push out unused gas, weakened gravity and allow dark matter to drift outward.
"Compared to the rest of the 60 or so Milky Way satellites, Ant 2 is an oddball," co-author Matthew Walker, a deputy professor at Carnegie Mellon University, revealed. "We wonder if this galaxy is just the tip of an iceberg, and the Milky Way is surrounded by a large population of almost invisible dwarves that are similar to this."
Solving the plaster can help researchers understand the universe's early origins.
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