The Milky Way is more warped than astronomers thought

An artist's rendition of the Milky Way galaxy side-on with Skowron's nearly 2,500 Cepheid stars plotted across the curved surface. Image courtesy of J. Skowron  OGLE

The Milky Way is more warped than astronomers thought

Despite these limitations, we know that the Milky Way is a spiral galaxy measuring around 120,000 light-years across, and that we're located around 27,000 light-years from the galactic core.

Astronomers from Warsaw University speculate that it might have been bent out of shape by past interactions with nearby galaxies.

Using that fluctuation, the team produced a 3D model of the galaxy, confirming work that previously demonstrated the galaxy was flared at its edges.

So Skowron and her team measured the distances between our sun and 2400 of these cepheid stars.

The two studies show very similar results, particularly in regard to the odd nature of the Milky Way's warped edges. "It is warped and twisted far away from the Galactic centre", study co-author Przemek Mroz said in a video. The first 3D map of the galaxy that showed this warped curve was published in February by researchers from the Chinese Academy of Sciences in Beijing.

This enables astronomers to calculate their distance with great precision.

"The internal structure and history of the Milky Way is still far from being understood, in part because it is extremely hard to measure distances to stars at the outer regions of our galaxy", she said. "This is a big percentage".

They say that warping may have been caused by past interactions with smaller galaxies within the Milky Way called satellite galaxies, or as a result of intergalactic gas and dark matter.

To make these hard measurements, Skowron's team looked for "cepheid" stars. These young, pulsating supergiants are ideal for this research because their brightness changes in a very regular pattern.

The Warsaw team used the same technique as the Beijing scientists for their new map, but factored in data from over 1000 more stars, some as remote as the boundary of the Milky Way's disk.

Dorota Skowron, lead author on the study and astronomer with Wroclaw University of Science and Technology, says the OGLE project observed the galactic disk of the Milky Way for six years, taking 206,726 images of the sky containing 1,055,030,021 stars.

The 1.3 metre Warsaw telescope in the Chilean Andes is used for the OGLE survey, and it can monitor the brightness of stars and measure their properties for years.

"So this is the most "real" map of the Milky Way", Skowron told Gizmodo.

"They essentially confirmed our earlier conclusions regarding the 3D shape of the Milky Way's disk, including its flaring in the outer regions", Chen said. They can be so bright that they can be observed at the very edge of the galaxy. "Yet they found pretty much the same result, which is comforting!"

Astronomers have presented a twist on how we see our galaxy, the Milky Way, with a new three-dimensional map. Skowron doesn't believe that seeing the other side will dramatically increase the number of Cepheids they find.

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