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MilkyWay @home An ancient dwarf galaxy rebuilt on a volunteer computer

Astrophysicists have reconstructed a dwarf galaxy shredded by a collision with the Milky Way. This is a discovery that may be useful in the search for dark matter. Credit: Rensselaer Polytechnic Institute

Astrophysicists first calculated the original mass and size of a dwarf galaxy that was shredded by a collision with the Milky Way billions of years ago. Reconstructing the original dwarf galaxy through which today’s stars pass through the Milky Way in a stellar “tide” helps scientists understand how the Milky Way-like galaxy was formed, and of ours. It may be useful for exploring the dark matter of the galaxy.


“We have been running simulations that incorporate this big trend. PerformerHeidi Newberg, a professor of physics, astrophysics and astronomy at Rensselaer Polytechnic Institute, said:From the data, and it’s the first big step to use the information to find Dark matter In the Milky Way. “

Billions of years ago, such other galaxies near the Dwarf Galaxy and the Milky Way were drawn into larger galaxies. As each dwarf galaxy merges with the Milky Way, the star becomes “Tidal force“The same kind of differential force that brings tidal forces to Earth. Tidal forces distort dwarf galaxies and eventually tear them, stretching the star into a tidal current that flies across the Milky Way. Such a merger of tidal forces. Is fairly common, and Newberg estimates that the “immigrant” stars absorbed by the Milky Way are galaxies, which are nearly spherical star clouds surrounding the spiral arms of the central disk. Consists of most of the halo stars.

Importantly, the position and velocity of the tidal stars carry information about the Milky Way’s gravitational field.

Dwarf galaxy reconstruction is data from Newberg’s MilkyWay @Home decentralized supercomputer utilizing 1.5 petaflops (computer processing speed measure) of home computer power provided by star surveys, physics, and volunteers. It is a research task that combines. This massive processing power allows us to simulate the destruction of dwarf galaxies of various shapes and sizes and identify the model that best matches the tides of the stars we see today.

“This is a huge problem. We solve it by running tens of thousands of different simulations until we get a real match. It’s done with the help of many volunteers around the world. It requires computer power. Newberg says, “We’re doing a brute force attack on MilkyWay @ Home, but given how complex the problem is, there are many benefits to this method. I think. “

As released today Astrophysical JournalNewberg’s team estimates that the total mass of the original galaxy in which today’s stars form the Orphan-Chenab River is 2×10.7 Double the mass of our sun.

However, it is estimated that only over 1% of its mass is composed of ordinary matter such as stars. The rest are thought to be fictitious matter called dark matter that exerts gravity, but they do not absorb or emit light and cannot be seen. The presence of dark matter will explain the discrepancy between the mass gravitational force we can see and the much greater gravitational force needed to explain the formation and movement of galaxies. It is estimated that the gravitational pull from dark matter accounts for 85% of the matter in the universe, and the tides of stars that have fallen into the dwarf galaxy can be used to determine where the dark matter is in the galaxy.

“Tide stars are the only stars in our galaxy whose positions can be known in the past,” said Dr. Newberg. “By looking at the current velocities of the stars along the tide and knowing that they are all in about the same place and moving at the same velocity, how much gravity changes along the tide. You can know. We have dark matter in the Milky Way. “

Studies have also found that the precursors of the Orphan-Chenab River have less mass than those measured in the suburbs of our galaxy today. To create a large galaxy like our Milky Way.

Galactic halo expert Dr. Newberg is a pioneer in identifying stellar currents in the Milky Way. One day she hopes MilkyWay @ home will help measure more than the characteristics of a collapsed dwarf galaxy.Ideally she wants to fit many dwarves at the same time Galaxy, Their orbits, and the characteristics of the Milky Way galaxy itself. This goal is complicated by the fact that the characteristics of our galaxies have changed over billions of years, and that small galaxies fall and tear and take to create these tides.

“By carefully tracking the course of the stars drawn into the Milky Way, Dr. Newberg and her team have not only long since the dwarf galaxy was destroyed, but also the formation of our galaxy and its very physical characteristics. “.


Gaia reveals that most Milky Way galaxies are newcomers to the corners of our universe.


For more information:
Orphan-Estimation of mass and radial profile of dwarf galaxy precursors on the Chenab River, using Eric J. Mendelsohn et al, MilkyWay @ home, Astrophysical Journal (2022). DOI: 10.3847 / 1538-4357 / ac498a

Quote: MilkyWay @ home An ancient dwarf galaxy rebuilt on a volunteer computer (February 17, 2022) from https: //phys.org/news/2022-02-ancient-dwarf-galaxy-reconstructed-milkywayhome.html Acquired on February 17, 2022

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MilkyWay @home An ancient dwarf galaxy rebuilt on a volunteer computer

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