There’s trouble brewing at the Milky Way’s edge: new measurements show that a peculiar distortion of the galactic disk is moving slowly, contradicting previous reports.
Nobody is yet certain of the outcome that will be accurate. There are some significant issues regarding the genesis and structure of spiral galaxies throughout the universe.
Astronomers describe the Milky Way as a double-armed, flat disk-shaped spiral galaxy that is whirling and glittering with stars. However, astronomers have been aware that this representation is only partially correct since the middle of the twentieth century.
Our galaxy’s outermost regions are twisted, with some parts sagging down and others bending upward, like a vinyl record left on a hot plate, according to early observations in the radio region of the electromagnetic spectrum.
According to subsequent evidence, this phenomenon, known as a galactic warp, is typical of spiral galaxies, according to ofia Chrobáková, a doctorate candidate in astronomy at the Institute Viktor Astrophysics of the Canary Islands (IAC) in Spain.
According to Chrobáková, many theories have been put up to explain how the warp came into being, one of which is that it might have been brought about by nearby matter collapsing onto the galactic disk. In that instance, the distortion would probably be static or moving extremely slowly.
Other hypotheses contend that more dynamic processes, such as interactions with dark matter at the galaxy’s edge or tiny galaxies orbiting their larger siblings, pulling on them gravitationally and creating ripples, are what cause warps.
These principles would result in an active warp that might spin like a top, a movement known as precession.
“If we know how fast or if the warp rotates, it could be like a piece of a puzzle,” Chrobáková said. “It tells us a lot of information about how the warp was created.”
Last year, a team reported in the journal Nature Astronomy that our galaxy’s warp was spinning using data from the European Space Agency’s Gaia satellite, which gives ultraprecise measurements of the location of the Milky Way’s stars. A second paper, published in The Astrophysical Journal in December, confirmed these results, indicating that the warp was zipping along rather quickly, orbiting with a period of 600 million to 700 million years.
If this is the case, the procession will be roughly 10 times faster than previous models predicted, according to Chrobáková.
However, in a new study, she and her IAC co-author Martn López-Corredoira put the brakes on the previous measurements. Chrobáková and López-Corredoira found that the warp is traveling about 3.4 times faster than the results announced last year by looking at the identical Gaia data but modeling the features differently. Their findings were published in The Astrophysical Journal on May 13th.
“My research puts down this new breakthrough and says we are back to where we started,” Chrobáková said. “We call it an anti-discovery.”
However, the error bars on Chrobáková’s findings are large enough to leave the matter unsolved, according to Ronald Drimmel, an astronomer at Italy’s University of Turin who was part of the team that first measured a precessing warp.
He told Live Science that the signal “could be signalling that there’s no motion, or that it has a tremendous motion.” There is a great deal of uncertainty.
According to Drimmel, a significant portion of the discrepancy is caused by the fact that neither team lacks a firm grasp on the actual geometry of the warp itself. Such measures are challenging to make. Since we are in the galaxy’s disk, our view is limited by dust clouds.
Chrobáková concurred that more data is required to solve this issue. Gaia is anticipated to release a new catalog the following year, which might include further details on this topic.
That’s a good thing, because other galaxies are likely too far away to settle the debate. “The Milky Way is the galaxy we have the best chance of exploring in such detail,” Chrobáková said.
Reference(s): The Astrophysical Journal
