Face-on spiral galaxy, NGC 628


NASA’s James Webb space telescope has produced some stunning images of spiral galaxies

Published: 15 February 2024


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Wonderful new images of spiral galaxies have been released by the NASA telescope. They show clearly defined arms, which are brimming with stars, to their centres, where there may be old star clusters and – sometimes – active supermassive black holes. Only NASA’s James Webb Space Telescope can deliver highly detailed scenes of nearby galaxies in a combination of near- and mid-infrared light – and a set of these images has been released.

These Webb images are part of a large, long-standing project, the Physics at High Angular resolution in Nearby GalaxieS (PHANGS) program, which is supported by more than 150 astronomers worldwide, some at Oxford.

Before Webb took these images, PHANGS was already brimming with data from NASA’s Hubble Space Telescope, the European Southern Observatory’s Very Large Telescope’s Multi-Unit Spectroscopic Explorer, and the Atacama Large Millimeter/submillimeter Array, including observations in ultraviolet, visible, and radio light. Webb’s near- and mid-infrared contributions have provided several new puzzle pieces.

‘Webb’s new images are extraordinary,’ said Janice Lee, a project scientist for strategic initiatives at the Space Telescope Science Institute in Baltimore. ‘They’re mind-blowing even for researchers who have studied these same galaxies for decades. Bubbles and filaments are resolved down to the smallest scales ever observed, and tell a story about the star formation cycle.’

Excitement rapidly spread throughout the team as the Webb images flooded in. ‘I feel like our team lives in a constant state of being overwhelmed – in a positive way – by the amount of detail in these images,’ added Thomas Williams, a postdoctoral researcher at the University of Oxford in the United Kingdom.

IMAGE Caption: Face-on spiral galaxy, NGC 628, is split diagonally in this image: The James Webb Space Telescope’s observations appear at top left, and the Hubble Space Telescope’s on bottom right. Webb and Hubble’s images show a striking contrast, an inverse of darkness and light. Why? Webb’s observations combine near- and mid-infrared light and Hubble’s showcase visible light. Dust absorbs ultraviolet and visible light, and then re-emits it in the infrared. In Webb's images, we see dust glowing in infrared light. In Hubble’s images, dark regions are where starlight is absorbed by dust.