Scientists map out 1 million previously unknown galaxies

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Scientists map out 1 million previously unknown galaxies
Scientists map out 1 million previously unknown galaxies

SPACE experts have completed the most detailed survey of the southern sky ever attempted with radio waves.

Approximately one million undiscovered galaxies beyond the Milky Way have been added to an unprecedentedly detailed map of a section of space. Previous surveys of the cosmos usually take years to complete, but the Rapid ASKAP Continuum Survey, perched on CSIRO’s Australian SKA Pathfinder radio telescope (ASKAP) required less than two weeks.

In addition, the data gathered has created images five times more sensitive and twice as detailed as previous attempts.

The first detailed 30cm radio map of the southern sky, including everything a visible in the Southern Hemisphere, was conducted by Sydney University’s Molonglo Sky Survey.

To put this latest feat into context, this 2006 survey required almost a decade to observe 25 percent of the entire sky.

But CSIRO’s Astronomy and Space Science division was able this year to survey 83 percent of the sky in only 10 days.

The RACS survey produced 903 images, each requiring 15 minutes of exposure time.

These were then stitched together into one map covering the entire area of the southern sky.

The resulting panorama of the radio sky is all the more remarkable because most of the map’s bright points are entire galaxies, rather than individual stars.

Amateur astronomers are now invited to explore the southern skies for themselves by taking a virtual tour.

Scientists have identified approximately three million galaxies in the map, far more than the 260,000 galaxies identified during the Molonglo Sky Survey.

Mapping the universe is important for exactly the same reason why maps are required on Earth.

Similarly, maps of the stars provide experts with crucial context for research and statistical power.

They can consequently help inform how certain galaxies behave, such as whether they exist in clusters of companions or drift through space alone.

And the ability to conduct an all-sky survey is such a record time had an additional benefit.

Surprisingly little is known about how the radio sky evolves over timescales of days to months.

But the new work gives astronomers the opportunity to regularly revisit each of the three million galaxies and track any differences.

The CSIRO’s RACS survey was only made possible by quantum leaps forward in cutting-edge space technology.

Its engineers installed innovative “phased array feeds” radio receivers and high-speed digital signal processors specifically for ASKAP.

ASKAP will soon conduct even more sensitive surveys in different wavelength bands, such as visible and invisible light including as X-rays, ultraviolet light and infrared light.

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