Spotted, a Dark Matter creche and its monstrous baby galaxies

Chris Davies - Dec 4, 2015
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Spotted, a Dark Matter creche and its monstrous baby galaxies

A creche of monstrous baby galaxies, swaddled in dark matter and billions of light years from Earth, could help answer questions about how the known universe formed. Monstrous galaxies, rapid stellar incubators, are no longer a feature of the universe, though ten billion years ago they pumped out new stars up to thousands of times the rate of current production.

Although exactly what happened after rates slowed is unclear, scientists believe that the giant elliptical galaxies we now see are the direct descendants of the former monstrous galaxies.

Now, courtesy of the Atacama Large Millimeter/submillimeter Array (ALMA), a so-called nest of monstrous baby galaxies has been identified. Located 11.5 billion light-years away, it provided an opportunity to check theories that such points were bathed in dark matter.

That’s been the idea, anyway, but testing it has always proved troublesome. For a start, such galaxies are generally dusty, and so telescopes have struggled to pick up the radio waves emitting through that natural shield.

Through a combination of detective work to narrow down an area of the sky to check, and the ALMA’s huge resolution, a research team led by Hideki Umehata of the Japan Society for the Promotion of Science, along with Yoichi Tamura and Kotaro Kohno of the University of Tokyo, were able to gather enough data to check against results from visible light telescopes.

By comparing ALMA’s findings and visible light readings taken with the Subaru Telescope, it was concluded that a 3D web of invisible dark matter was present and acting as a nursery for new monstrous galaxies.

In fact, those young galaxies apparently lined up exactly at the points where dark matter filaments intersected.

The belief now is that the current large elliptical galaxies were, once, founded at those intersection points. Future research will examine other points of dark matter and how its distribution lines up with other monstrous galaxies.

SOURCE National Institutes of Natural Sciences


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