Images of five colourful galaxies

Galactic fireworks go off

An international team of astronomers has snapped stunning images of “galactic fireworks”, capturing stellar nurseries as they give birth to new stars.

These images focus on galaxies close to the Milky Way and show their different components in distinct colours, including the locations of clouds of gas and dust where infant stars are igniting. They were taken as part of the PHANGS (Physics at High Angular Resolution in Nearby GalaxieS) survey, which is using both ground and space-based telescopes to peer into these violent nurseries.

This image, taken by the Multi-Unit Spectroscopic Explorer (MUSE) on ESO’s Very Large Telescope (VLT), shows the nearby galaxy NGC 4303. NGC 4303 is a spiral galaxy, with a bar of stars and gas at its centre, located approximately 55 million light-years from Earth in the constellation Virgo. Credit: ESO/PHANGS

“By combining observations from some of the world’s most powerful telescopes, we can examine the galactic regions where star formation is happening, compared to where it is expected to happen,” says team member Rebecca McElroy from the University of Sydney.

“This will give us a chance to better understand what triggers, boosts or holds back the birth of new stars.”

These particular images were snaps by the European Southern Observatory’s Very Large Telescope (VLT), using a powerful instrument called the Multi-Unit Spectroscopic Explorer (MUSE). MUSE is an integral field spectrograph: it collects light across the visible spectrum, resulting in a “3D” image where each pixel contains multiple wavelengths of light.

As part of PHANGS, MUSE has collected 15 million spectra of various galactic regions, spanning 30,000 clouds of warm gas where stars could form.

This image, taken with the Multi-Unit Spectroscopic Explorer (MUSE) on ESO’s Very Large Telescope (VLT), shows the nearby galaxy NGC 1300. Credit: ESO/PHANGS

Further images from PHANGS have been taken by the Atacama Large Millimetre/submillimetre Array (ALMA), which looks at a different region of the electromagnetic spectrum and enables researchers to survey clouds of colder gas; so far, it has observed 100,000 gas regions across 90 galaxies.

“By combining these observations with those from ALMA, we’re able to see newborn stars while they’re still surrounded by the blanket of gas they’ve formed from,” says Brent Groves, from the University of Western Australia node of the International Centre for Radio Astronomy Research (ICRAR).

“The resulting images are absolutely stunning – they allow us a spectacularly colourful insight into the stellar nurseries of our neighbouring galaxies.”

Further observations planned with NASA’s James Webb Space Telescope will allow astronomers to scrutinise star-forming processes into infra-red light.

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