[ad_1]
Posted on May 16, 2019
A huge "something" seems to have torn a hole in a part of the Milky Way halo. The "dark substructure" was discovered via observations of the Gaia probe – a mission producing the most detailed 3D map of our galaxy – Ana Bonaca of Harvard noticing a disturbance in a tidal stream. Bonaca is a leading authority on how the tide field of the Milky Way galaxy disrupts globular clusters and what the resulting debris can tell us about the underlying distribution of dark matter.
As Bonaca says, the "disruptive" is unknown – "It's a dense ball of something," she told the LiveScience website. The hole is huge, so whatever it is, it must be too. "It's a lot bigger than a star. Something like a million times the mass of the sun. So, there are simply no stars of this mass. We can exclude it. And if it was a black hole, it would be a supermassive black hole of the kind that we find at the center of our own galaxy. "
Hubble and Gaia – "Measure the Milky Way and its Envelope of Dark Matter"
If there is nothing that bothers them, the streams are almost uniform in terms of density. However, Bonaca noticed that there was a hole in one hole during his recent presentation at the American Physical Society conference in Denver during his talk on Dynamic Evidence for a Substructure dark in the halo of the Milky Way: "Morphology on sky suggests with a massive and dense disruption", a summary of his work.
The telescope observations show no large luminous object moving away from the hole, which led Bonaca to suggest that the disturbance could have been caused by the dark matter. "The observations allow a low mass dark matter subhalo as a plausible candidate," explains the Bonaca abstract.
"The hidden past of the Milky Way" – Gaia unveils an object of dark matter 1 to 100 million times the mass of the sun
If it was a dense mass of dark matter that was crossing the tidal current, it would be an interesting discovery for scientists because it would give them the opportunity to study the elusive substance . The discovery of a "ball" of dark matter would also fit with current predictions about the nature of dark matter – research suggests that it is "bundled" in the sense that it does not exist. Is not smooth and evenly distributed in the universe.
Gaia Mission – "Something sent powerful waves into our galaxy 300 to 900 million years ago"
Identifying a cluster of dark matter "opens the possibility that detailed observations of watercourses can measure the mass spectrum of dark matter substructures and even identify individual substructures," concludes his summary.
The first accurate 3D map of our galaxy revealed its real shape: distorted and twisted. Astronomers from Macquarie University and the Chinese Academy of Sciences used 1339 "standard" stars to map the actual shape of our natal galaxy in an article published today in Nature Astronomy. The image of the artist, Chen Xiaodian, of the distorted and twisted Milky Way disk is shown at the top of the page.
An international team of astronomers discovered that the Milky Way's disk of stars was becoming increasingly "deformed" and twisting as the stars moved away from the center of the galaxy. "We generally think that spiral galaxies are fairly flat, like Andromeda, which you can easily see at the telescope," says Professor Richard de Grijs, astronomer of the Australian University Macquarie.
The Daily Galaxy via Ana Bonaca, a dynamic proof for a dark substructure in the Milky Way Halo and Live Science
[ad_2]
Source link