A set of highly detailed images of 19 nearby spiral galaxies from NASA’s James Webb Space Telescope have been publicly released today. The suite of extraordinary images will provide several new puzzle pieces for astronomers and astrophysicists around the world.
The images are part of a long-standing project, the Physics at High Angular resolution in Nearby GalaxieS (PHANGS) programme, which is supported by more than 150 astronomers worldwide. These latest images from JWST’s near- and mid-infrared spectrographs join the programme’s vast body of data gained from NASA’s Hubble Space Telescope, the Very Large Telescope’s Multi-Unit Spectroscopic Explorer, and the Atacama Large Millimeter/submillimeter Array. This means that researchers now have ground-based and space-based observation data in ultraviolet, visible, and radio light data as well as the near- and mid-infrared imagery.
Dr Thomas Williams, a postdoctoral researcher at the Department of Physics at the University of Oxford led on the data processing for the latest set of images – some 18 months of work for a team of around 10 people: ‘The amount of detail in these images is overwhelming – in a good way,’ he explains. ‘It means that we may be able to fill in more of the gaps in our knowledge about the structure and evolution of galaxies, star formation, the life-cycle of stars and so much more.
‘We have been hard at work getting these data ready for science. This programme is a huge volume of data, and JWST is an extremely complex observatory. Working with the data so early in JWST’s lifecycle has been a privilege and a challenge, and we have learnt a lot that will improve JWST observations going forwards. The images, I think, speak for themselves: this is the sharpest view we have ever had of galaxies at these wavelengths.’
JWST’s NIRCam (Near-Infrared Camera) captured millions of stars in the images, which sparkle in blue tones. Some stars are spread throughout the spiral arms, but others are clumped tightly together in star clusters. The telescope’s MIRI (Mid-Infrared Instrument) data highlights glowing dust, showing where it exists around and between stars. It also spotlights stars that haven’t yet fully formed – they are still encased in the gas and dust that feed their growth, like bright red seeds at the tips of dusty peaks. JWST’s images also show large, spherical shells in the gas and dust.
Evidence shows that galaxies grow from inside out – star formation begins at galaxies’ cores and spreads along their arms, spiralling away from the centre. The farther a star is from the galaxy’s core, the more likely it is to be younger. In contrast, the areas near the cores that look lit by a blue spotlight are populations of older stars while some galaxy cores are awash with pink and red diffraction spikes.
‘There are so many avenues of research that scientists can pursue with the combined PHANGS data,’ continues Dr Williams. ‘The unprecedented number of stars in evidence from this latest suite of images has huge potential for cataloguing and learning.’
In addition to immediately releasing these images, the PHANGS team has also released the largest catalogue to date of roughly 100,000 star clusters. ‘The amount of analysis that can be done with these images is vastly larger than anything our team could possibly handle,’ concludes Professor Erik Rosolowsky from the University of Alberta, Canada, one of the project leads. ‘We’re excited to support the community so all researchers can contribute.’
The James Webb Space Telescope is an international programme led by NASA with its partners, ESA (European Space Agency) and the Canadian Space Agency.