Meet Maggie: The Largest Structure in the Milky Way Located 55,000 Light-Years Away From Earth

Astronomers from the Max Planck Institute of Astronomy (MPIA) led an international scientific collaboration to find the largest structure in the Milky Way. This massive hydrogen filament called Maggie is 3,900 light-years long, wherein one light-year is equivalent to 5.87 trillion miles, and 130 light-years wide that likely formed 13 million years ago.

Juan Soler, the project's co-author, was one of the first astronomers to find the clue to this object a year ago and decided to name it after Colombia's longest river, Rio Magdalena. He said in a statement that the current study only proves beyond doubt that what he found is indeed a coherent structure.

Physical Properties of the Maggie Filament

Around 380,000 years after the Big Bang, hydrogen was formed and is considered the most abundant substance in the universe, Mail Online reported. Despite that, scientists said that detecting the gas is such a grueling task, which makes Maggie's recent discovery exceptionally exciting.

Study first author Jonas Syed, a Ph.D. student at MPIA, said in the statement that the location of this filament has contributed to the success of their discovery. They are unsure how it got there, but the hydrogen filament extends about 1,600 light-years below the Milky Way plane.

Based on their observations, the hydrogen's radiation at about eight inches of wavelength stands out in the background and makes the hydrogen filament more visible. A deeper analysis of Maggie also showed that the gas converges at some points in the filament where hydrogen is likely to accumulate and condense into larger clouds.

Researchers wrote in their study, titled "The "Maggie" Filament: Physical Properties of a Giant Atomic Cloud" published in the journal Astronomy & Astrophysics, that those are the kind of environment where atomic gas slowly changes into a molecular form. At Maggie's west end is a hub-like feature that smaller scale filaments seem to converge while its tail thins on its western part.

Meanwhile, its northwestern part is connected to the midplane that feeds off the material on the higher latitudes. Although, most of Maggie is disconnected from the Galactic midplane material. Researchers estimated that Maggie contains 8% molecular hydrogen.

In an interview with Universe Today, Syed said that many questions remain about the largest structure in the Milky Way galaxy. They hope to gain additional data about it and are now waiting for a fraction of the molecular gas to be analyzed.

What Does the Gaia Satellite Do?

The astronomers used the European Space Agency's (ESA) Gaia satellite to measure Maggie. According to ESA, the Gaia is an ambitious mission designed to chart a 3D map of the Milky Way galaxy. I the process of doing so, it detected the hydrogen filament.

Moreover, the Gaia satellite can reveal the galaxy's composition, formation, and evolution by providing accurate and unprecedented positional and radial velocity measurements that will create a census about the billions of stars in the galaxy.

Thanks to the Gaia satellite, scientists were able to make numerous discoveries in the past years, including the 12 quasars whose light is so strongly deflected by other galaxies and make them more visible to form distinct images of what they call the "Einstein cross."

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