Webb peers behind near-infrared bars
A delicate tracery of dust and bright star clusters threads across this image from the NASA/ESA/CSA James Webb Space Telescope. This view from Webb’s NIRCam instrument is studded by the galaxy’s massive population of stars, most dense along its bright central bar, along with burning red clouds of gas illuminated by young stars within. These glittering stars belong to the barred spiral galaxy NGC 5068, located around 17 million light-years from Earth in the constellation Virgo.
This portrait of NGC 5068 is part of a campaign to create an astronomical treasure trove, a repository of observations of star formation in nearby galaxies. Previous gems from this collection can be seen here and here. These observations are particularly valuable to astronomers for two reasons. The first is because star formation underpins so many fields in astronomy, from the physics of the tenuous plasma that lies between stars to the evolution of entire galaxies. By observing the formation of stars in nearby galaxies, astronomers hope to kick-start major scientific advances with some of the first available data from Webb.
The second reason is that Webb’s observations build on other studies using telescopes including the NASA/ESA Hubble Space Telescope and some of the world’s most capable ground-based observatories. Webb collected images of 19 nearby star-forming galaxies which astronomers could then combine with catalogues from Hubble of 10 000 star clusters, spectroscopic mapping of 20 000 star-forming emission nebulae from the Very Large Telescope (VLT), and observations of 12 000 dark, dense molecular clouds identified by the Atacama Large Millimeter/submillimeter Array (ALMA). These observations span the electromagnetic spectrum and give astronomers an unprecedented opportunity to piece together the minutiae of star formation.
This near-infrared image of the galaxy is filled by the enormous gathering of older stars which make up the core of NGC 5068. The keen vision of NIRCam allows astronomers to peer through the galaxy’s gas and dust to closely examine its stars. Dense and bright clouds of dust lie along the path of the spiral arms: these are H II regions, collections of hydrogen gas where new stars are forming. The young, energetic stars ionise the hydrogen around them which, when combined with hot dust emission, creates this reddish glow. H II regions form a fascinating target for astronomers, and Webb’s instruments are the perfect tools to examine them, resulting in this image.
[Image Description: A close-in image of a spiral galaxy, showing its core and part of a spiral arm. At this distance thousands upon thousands of tiny stars that make up the galaxy can be seen. The stars are most dense in a whitish bar that forms the core, and less dense out from that towards the arm. Bright red gas clouds follow the twist of the galaxy and the spiral arm.]
