The Large Magellanic Cloud is a well-known satellite or dwarf galaxy that orbits the Milky Way closely and is visible in Earth’s southern hemisphere. RIT researchers make the case for the existence of “missing” satellite galaxies that are cloaked in dark matter and cannot be directly observed. (Image Credit: ESA/NASA/Hubble)
The Large Magellanic Cloud is a well-known satellite or dwarf galaxy that orbits the Milky Way closely and is visible in Earth’s southern hemisphere. RIT researchers make the case for the existence of “missing” satellite galaxies that are cloaked in dark matter and cannot be directly observed. (Image Credit: ESA/NASA/Hubble)
Space

Confirmed – Galaxies Coexist with Dark Matter at the Edge of the Milky Way

Scientists at Rochester Institute of Technology have shed new light on a problematic structure at the poles of the Milky Way. The huge structure is at the center of a tug of war between scientists and the new research eliminates a challenge to the accepted standard model of the universe and theory of how galaxies form.

Scientists are divided about the existence of dark matter, the invisible substance that, according to some scientists, comprises 85 percent of the mass of the universe. In the study, the standard cosmological model, or the Cold Dark Matter paradigm, is reinforced. Researchers show that the huge polar structure is an unstable structure and that it formed well after the Milky Way. The paper has been accepted for publication in the Monthly Notices for the Royal Astronomical Society.

Chakrabarti and Lipnicky compared simulations of the “missing” or sub-halo dwarf galaxies that are thought to be cloaked in dark matter, to the distribution of the classical Milky Way dwarf galaxies that form the polar structure.

The authors used motion measurements to trace the orbits of the classical Milky Way satellites backward in time. The simulations revealed that the polar structure is breaking up and dispersing. This indicates that the plane was formed later in the evolution of the galaxy and is not as old as what was initially believed. Chakrabarti noted that the vast polar structure of satellite galaxies might therefore be a temporary feature.

Chakrabarti added that it would have been a different story if the planar structure lasted for a long time, as it would not disperse so quickly if that were the case. This finding shows that the structure is not dynamically stable. He also pointed out that there is no inconsistency between the present cosmological paradigm and dwarf galaxies’ planar structure.

The orbital analyses determined that the dwarf galaxies Leo I and Leo II were not part of the original polar structure. When this became apparent, the authors removed these classical Milky Way satellites from the study. The dwarf galaxies are later additions probable snatched from the Milky Way. When a comparison is done by excluding Leo I and II, a similar plane shared by classical galaxies and their cloaked counterparts is revealed.

Lipnicky noted that many different combinations of the dwarf galaxies were tried, including distributions of dwarfs that share similar orbits. It was however found that in the end, the plane always dispersed very quickly.

There are scientists that reject the existence of dark matter. This group questions the standard cosmological paradigm that agrees that a hidden plane of dark matter cloaked galaxies and a vast polar structure of satellite galaxies can co-exist.

This study refutes the challenge to the accepted standard model of the universe and backs the co-existence of these structures.