Webb peers behind mid-infrared bars
A delicate tracery of dust and bright star clusters threads across this image from the NASA/ESA/CSA James Webb Space Telescope. In this image, from Webb’s MIRI instrument, the dusty structure of the spiral galaxy and glowing bubbles of gas containing newly-formed star clusters are particularly prominent. These bright tendrils of gas 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.
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?
[Image description: A close-in image of a spiral galaxy, showing its core and part of a spiral arm. A few bright stars are visible throughout it, concentrated in the barred core. Clumps and filaments of dust thread through it, forming an almost skeletal structure that follows the twist of the galaxy and its spiral arm. Large, glowing bubbles of red gas are hidden in the dust.]
