ALMA spots young galaxies swathed in dark matter

TOKYO, Dec. 4 (UPI) -- A team of astronomers discovered a cluster of massive baby galaxies 11.5 billion light-years away using the telescopic powers of the Atacama Large Millimeter/submillimeter Array, or ALMA.

ALMA's observations offer astronomers a trip back through time, capturing the light of galaxies from the early universe. Ten billion years ago, giant young galaxies were common, featuring star-formation rates thousands of times greater than the Milky Way's.

The modern universe is without giant galaxies, but astronomers think these monstrous baby galaxies evolved to become the massive elliptical galaxies seen today.

Giant young galaxies, such as those imaged by ALMA, are often shrouded in dust, making them difficult to pinpoint.

Previous surveys of a small part of the small portion of the sky named SSA22 in the constellation Aquarius suggested the presence of these expansive, star-rich galaxies, but other radio telescopes aren't powerful enough to gather details in specific galaxies. ALMA was able to offer ten times the sensitivity and 60 times the resolution of previous imaging attempts.

When researchers in Japan compared the ALMA findings with visible light scans taken by the National Astronomical Observatory of Japan's Subaru Telescope, they found the galaxy cluster was situated at a knotting of dark matter -- part of the cosmic web that dictates where and how cosmic matter congregates.

The new findings, published in the Astrophysical Journal Letters, support the cosmic evolution models that predict the presence of large elliptical galaxies near the nexuses of large dark matter filaments.