The Milky Way collided with a "sausage galaxy" in the early years and so permanently changed its structure |



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The internal bulge structure of the galaxy and external silver halo has long intrigued astronomers, and now we can know the reason. A new international study has shown that 80 to 10 billion years ago, unknown dwarf galaxies crashed into our Milky Way and did not survive, fragmented and scattered, thus altering permanently the structure of the Milky Way.

The team is composed of experts from the University of Cambridge, Carnegie Mellon University and the Institute of Astrophysics of the Flatiron Institute of New York. , using the Gaia and Sloan Digital Survey (Sloan Digital) Sky Survey, SDSS, Note) Data captures the speed, trajectory and position of stars The astronomer of the University of Cambridge, Vasily Belokurov, says that a detail of ancient and dramatic galactic collision is hidden in the speed and chemical composition of the star.

There were many dwarf galaxies falling into the Milky Way, for example a small melting on the Milky Way corner 100 million years ago: the collision sound "sounds like a bell", and even the Milky Way with Sagittarius. Sacred galaxies (Sagittarius dwarf galaxy) merge, but the collapse of 80 to 10 billion years ago was a decisive event in remodeling the structure of the Milky Way. Although compared to the Milky Way, the size of dwarf sausage galaxies is small, but its total mbad is also more than 10 billion times the mbad of the sun.

In this collision, the Milky Way completely tore the dwarf galaxies from minced meat sausages, which basically disappeared completely, leaving only a few remnants combined – stars whose orbits become super-extreme are available for tracing. For this, the surface of the Milky Way must be regenerated, fragments of Sausage galaxies are dispersed in the Milky Way, resulting in the internal convexity of the Milky Way and the formation of a silver halo around the surface of the disc after remodeling. Currently, the distance between the stars brought by the dwarf galaxies and the silver nucleus is about the same as that of the comets in the solar system.When the surface of the disc is stretched, the orbit is lengthened , like a needle. But if you want to find these stars from the bottom data graph, well, you can use a little imagination.

(Source: Astrophysical Center of the Institute of Iron Research)

With these data, astronomers can trace the distant past of the Milky Way and predict the future . Within 4 billion years, the Andromeda galaxy will slowly collide with the Milky Way, and the shape of the Milky Way could change. The new document was published in the Royal Astronomical Society Monthly.

Note: The Sloan Digital Sky Survey (SDSS) is a redshift survey using the 2.5-meter telescope of the Apache Point Observatory to observe 25% of the sky and acquire more than 1 million celestial bodies. Multicolored counting data and spectral data.

(Source: Carnegie Mellon University)


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