Posted on 12/20/2021 10:04:13 AM PST by Red Badger
The new map has revealed a new substructure of the Milky Way’s outer disk using data from the Gaia space misison. Credit: C. Laporte et al. (MNRAS, 2021)
An international team of astronomers led by researcher Chervin Laporte of the Institute of Cosmos Sciences of the University of Barcelona (ICCUB-IEEC) has revealed a new map of the Milky Way’s outer disk using data from the Gaia space misison. The findings have been published in the journal Monthly Notices of the Royal Astronomical Society.
“Typically, this region of the Milky Way has remained poorly explored due to the intervening dust which severely obscures most of the Galactic midplane”, says Chervin Laporte, first signer of the article. “While dust affects the luminosity of stars, it has no effect on their motion. As a result, one can use the stars’ motion to perform a tomography of the Galaxy’s outermost regions,” adds the ICCUB researcher. The team analyzed the Gaia motion data, available from December 2020, to identify coherent structures.
The map reveals the existence of many previously unknown coherently rotating filamentary structures at the edge of the disk. It also gives a sharper global view of previously known structures. Numerical simulations predict such filamentary structures to form in the outer disk from past satellite interactions, however the sheer quantity of substructure revealed by this map was not expected and it remains a mystery.
The new map has revealed a new substructure of the Milky Way’s outer disc using data from the Gaia space misison. Credit: C. Laporte et al. (MNRAS, 2021)
What could these filamentary structures be?
Our Galaxy is surrounded by fifty satellite galaxies and has engulfed numerous galaxies in its past. At present, the Milky Way is thought to have been perturbed by the Sagittarius dwarf galaxy, a fact that confirmed Laporte’s earlier theoretical models. However, in its more distant past it interacted with another intruder, the Gaia Sausage, which has now dispersed its debris into the stellar halo. The researchers formulated the hypothesis that states that these filamentary structures are remains of tidal arms from the Milky Way disk, which were excited at different times by various satellite galaxies.
Laporte notes that in an earlier study, they already showed that one of the thread-like structures in the outer disk, called the Anticenter Stream, had stars that were predominantly older than eight billion years, “making it potentially too old to have been caused by Sagittarius alone, but more in line with a Sausage origin. “Another possibility,” adds the researcher “would be that not all these structures are actually genuine disk substructures, but instead form the crests of vertical density waves in the disk seen in projection, forming an optical illusion that the disk is highly substructured.”
The team has secured a dedicated follow-up program with the WEAVE spectrograph to study the similarities and differences in stellar populations in each substructure. Through the study of radial velocities, chemical abundances, and potentially stellar ages, the upcoming surveys WEAVE, SDSS-V, and PFS will also shed light into the origins of the substructures.
Reference: “Kinematics beats dust: unveiling nested substructure in the perturbed outer disc of the Milky Way” by Chervin F P Laporte, Sergey E Koposov, Vasily Belokurov, 18 October 2021, Monthly Notices of the Royal Astronomical Society: Letters. DOI: 10.1093/mnrasl/slab109
It may be the Galaxy’s wall to keep the illegal aliens out. ;-)
“the Gaia Sausage”
A cosmic dildo of sorts?
A hundred years ago the mathematicians “created” a universe that was calm and in order and in balance and everyone is happy. Then better and better observing instruments kept find anomalies and exceptions and all those mathematical “truths” evaporated. Welcome to the universe of chaos. The more you see the less you know. It keeps it all interesting.
Not a mystery...
It’s the Milky Way galaxy’s structure...
It is what it is...
It’s the Thing. You know...the THING.
it is just the containment wall to keep politicians from Earth from contaminating the rest of the universe
The ‘natural state’ of the Universe is chaos...................
Note the ‘tail’ descending from the approximate center, curving down, and then rising up becoming dense at its tip. Defensive structure to keep galactic alien matter at bay?
Outposts of a machine civilization?
The Berserkers are heading our way.
Big Green WM dumpsters. Where else they gonna put them?
I really hope that the ‘Gaia sausage’ doesn’t interact with Uranus...that could get messy!
The universe is nothing more than an illusion. One perceives what they want to perceive. One gives meaning to what they want to give meaning. All perception is untrue. Truth never changes. Perception always changes depending on the perceiver.
Just police crime scene barriers, that’s all.
💯
The new map has revealed a new substructure of the Milky Way’s outer disk using data from the Gaia space mission.
That's some smart substructure! /jk
MY GOD! It’s full of stars!
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