James Webb Space Telescope Discovery

Webb peers behind bars

A delicate tracery of dust and bright star clusters threads across this image from the NASA/ESA/CSA James Webb Space Telescope. The bright tendrils of gas and stars belong to the barred spiral galaxy NGC 5068, whose bright central bar is visible in the upper left of this image. NGC 5068 lies 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. With its ability to peer through the gas and dust enshrouding newborn stars, Webb is the perfect telescope to explore the processes governing star formation. Stars and planetary systems are born amongst swirling clouds of gas and dust that are opaque to observations in visible light, like many from Hubble or the VLT. The keen vision at infrared wavelengths of two of Webb’s instruments — MIRI and NIRCam — allowed astronomers to see right through the gargantuan clouds of dust in NGC 5068 and capture the processes of star formation as they happened. This image combines the capabilities of these two instruments, providing a truly unique look at the composition of NGC 5068. Credit: ESA/Webb, NASA & CSA, J. Lee and the PHANGS-JWST Team NGC 5068 (NIRCam + MIRI image) Three asteroid trails intrude into this image, visible as tiny blue-green-red dots. Asteroids appear in astronomical images such as these because they are much closer to the telescope than the distant target. As Webb captures several images of the astronomical object, the asteroid moves, so it shows up in a slightly different place in each frame. They are a little more noticeable in images such as this one from MIRI, because many stars are not as bright in mid-infrared wavelengths as they are in near-infrared or visible light, so asteroids are easier to see next to the stars. One trail lies just below the galaxy’s bar, and two more in the bottom-left corner - can you spot them? NGC 5068 (MIRI image) - Partial image, high res NGC 5068 (MIRI image) - Full image, low res 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: within these are young, massive star clusters and 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. YOung star-forming regions are a fascinating target for astronomers, and Webb’s instruments are the perfect tools to examine them, resulting in this image. NGC 5068 (NIRCam image) Raw images