The NASA/ESA/CSA James Webb Space Telescope presents a stunning collection of near- and mid-infrared portraits capturing 19 face-on spiral galaxies. These detailed images, showcasing stars, gas, and dust on unprecedented scales beyond our own galaxy, are a testament to the telescope’s groundbreaking capabilities. Researchers are delving into the imagery to unravel the origins of these intricate structures, providing valuable insights into star formation and the evolution of spiral galaxies.
This treasure trove of images is part of the Physics at High Angular resolution in Nearby GalaxieS (PHANGS) program, supported by over 150 astronomers globally. Prior to Webb’s contributions, PHANGS had amassed data from the NASA/ESA Hubble Space Telescope, the Very Large Telescope’s Multi-Unit Spectroscopic Explorer, and the Atacama Large Millimeter/submillimeter Array. Webb’s near- and mid-infrared observations add new dimensions to this comprehensive dataset.
Webb’s Near-Infrared Camera (NIRCam) captured millions of stars, illuminating the spiral arms in mesmerizing blue tones. Some stars are dispersed across the arms, while others cluster tightly into star formations. The Mid-Infrared Instrument (MIRI) data reveals glowing dust, exposing its presence behind, around, and between stars. This instrument also highlights stars in the early stages of formation, shrouded in the gas and dust feeding their growth.
Astronomers were astounded to find large, spherical shells in the gas and dust, potentially formed by exploded stars. Extended regions of gas in the spiral arms, depicted in red and orange, offer insights into a galaxy’s distribution of gas and dust. Understanding these structures is crucial for unraveling how galaxies initiate, sustain, and conclude star formation.
The imagery showcases evidence that galaxies grow from the inside out, with star formation originating at their cores and spiraling outward along the arms. The varying colors indicate the age of stars, with younger stars farther from the galaxy’s core. Additionally, pink-and-red diffraction spikes near galaxy cores suggest active supermassive black holes or saturation from bright star clusters.
The combined PHANGS data, coupled with Webb’s unrivaled resolution of stars, opens up myriad avenues for scientific exploration. In a groundbreaking move, the PHANGS team has released not only the images but also the largest catalogue to date, featuring approximately 100,000 star clusters. This collaborative effort promises to deepen our understanding of galactic dynamics and stellar evolution.