The James Webb Space Telescope has recently captured breathtaking images of 19 spiral galaxies, providing astronomers with an unprecedented level of detail. These scintillating portraits showcase the millions of stars that reside within each galaxy, offering a unique perspective on their intricate structures. What sets Webb apart is its ability to observe the universe in various wavelengths of infrared light, such as near-infrared and mid-infrared, allowing for a deeper understanding of star formation and the evolution of spiral galaxies.
Spiral galaxies make up approximately 60% of all galaxies, including our very own Milky Way. By studying these galaxies, astronomers can gain valuable insights into the processes that shape our own cosmic home. The new images captured by Webb reveal spiral arms adorned with stars, with clusters of old stars or supermassive black holes at the center of each galaxy.
These stunning observations were made as part of the Physics at High Angular resolution in Nearby GalaxieS (PHANGS) project, which involves over 100 astronomers from around the world. The project combines data from multiple telescopes, including the Hubble Space Telescope, the European Space Observatory’s Very Large Telescope’s MUSE instrument, and the Atacama Large Millimeter/submillimeter Array in Chile. By utilizing different telescopes and wavelengths of light, astronomers can fill in observational gaps and gain a more comprehensive understanding of these galaxies.
Janice Lee, a PHANGS core member and project scientist for new missions and strategic initiatives at the Space Telescope Science Institute, expressed her excitement about Webb’s new images, stating that they are “extraordinary” and “mind-blowing.” The images reveal intricate details, such as bubbles and filaments, on the smallest scales ever observed. These details provide valuable insights into the star formation cycle within these galaxies.
Webb’s Near-Infrared Camera allows astronomers to observe millions of stars, which appear as sparkling blue clusters throughout the arms of the galaxies. Additionally, Webb’s Mid-Infrared Instrument focuses on the glowing dust surrounding the stars and the red still-forming stars cocooned within the gas and dust that facilitate their growth. Erik Rosolowsky, a PHANGS core member and professor of physics at the University of Alberta, explains that these regions are where the newest and most massive stars in the galaxies can be found.
The images captured by Webb also reveal spiral arms illuminated by orange and red gas, providing valuable information about the distribution of gas and dust within spiral galaxies. Rosolowsky likens these structures to waves, with their spacing offering insights into how galaxies distribute their gas and dust. Webb also captured spherical shell-shaped voids amidst the galactic gas and dust, which are believed to have been created by the explosions of stars.
Adam Leroy, a PHANGS core member and professor of astronomy at the Ohio State University, explains that galaxies form from the inside out, with star formation beginning at the galactic center before rippling across the arms in a spiral. This means that a star’s distance from the heart of the galaxy is relative to its age, with younger stars likely being farther from the galactic core. The presence of blue stars near the centers of each galaxy indicates the presence of older stars. Some galaxies also exhibit pinkish-red spikes near their centers, suggesting the presence of an active supermassive black hole or exceptionally bright star clusters.
Scientists are particularly excited about studying the vast number of stars revealed by Webb’s new images. By cataloging different types of stars and their characteristics, astronomers can gain a more comprehensive understanding of their life cycles, which can span billions or trillions of years.
The James Webb Space Telescope’s unprecedented images of spiral galaxies have opened up new avenues for exploration and understanding in the field of astronomy. These captivating portraits provide astronomers with valuable insights into star formation, galaxy evolution, and the intricate structures of spiral galaxies. With its ability to observe the universe in different wavelengths of infrared light, Webb continues to push the boundaries of our knowledge and inspire awe and wonder in the depths of space.