These stunning images of spiral galaxies captured by the James Webb Space Telescope (JWST) as part of the Physics at High Angular resolution in Nearby GalaxieS (PHANGS) programme, showcase the incredible detail of 19 spirals in face-on imaging mode. The galactic arms with their multitudes of stars are illuminated in infrared light, as are the dense galactic cores, where supermassive black holes reside.
The PHANGS program is a long-term initiative aimed at understanding how gas and star formation interact with galactic structure and evolution. One of the JWST’s four primary science goals is to study how galaxies form and evolve, and the PHANGS program plays a pivotal role in that effort.
The JWST’s unique ability to capture both near-infrared (NIR) and mid-infrared (MIR) light reveals more details than even the powerful Hubble Space Telescope, which operates in visible light, UV light, and a small portion of infrared light. The red color in these high-resolution images represents gas and dust emitting infrared light, which the JWST is particularly adept at detecting.
Some images show bright diffraction spikes in the galactic center, suggesting that a supermassive black hole is active or that there is an extremely high concentration of stars.
Read More News: Astronomers have obtained a fresh image of the black hole located in galaxy M87
If you’re fascinated by nature, these images of spiral galaxies are sure to captivate your imagination.
“That’s a clear sign that there may be an active supermassive black hole,” said Eva Schinnerer, a staff scientist at the Max Planck Institute for Astronomy in Heidelberg, Germany. “Or, the star clusters toward the center are so bright that they have saturated that area of the image.”
Stars located closer to the center of a galaxy are generally older than those found in the arms. Conversely, the further a star is from the galactic center, the younger it is likely to be. These younger stars have a blue hue and have cleared away the gas and dust that surrounded their formation. In contrast, orange clumps indicate even younger stars that are still shrouded in their cocoon of gas and dust, actively accreting material and forming.
“These are where we can find the newest, most massive stars in the galaxies,” said Erik Rosolowsky, a professor of physics at the University of Alberta in Edmonton, Canada.
New images have been released by the PHANGS observing program, which uses different telescopes to observe galaxies in visible light, infrared light, UV light, and radio. These images were compared to some of the Hubble telescope’s views of the same galaxies. The comparison highlights how observing different wavelengths of light reveals or obscures different details in the galaxies.
Since the human eye cannot detect infrared light, different visible colors are assigned to different wavelengths of light to make the images meaningful. In the JWST image of NGC 628 above, the galaxy’s center is filled with old stars that emit some of the shortest wavelengths of light the telescope can detect. These stars have been given a blue color to make them visible.
On the other hand, in the Hubble image of the same region, the galaxy’s center appears more yellow and washed out. This is because the Hubble telescope can only sense the longest wavelengths of light emitted by the region. As a result, it has different color assignments than the JWST.
It’s worth noting that Janice Lee, a project scientist at the Space Telescope Science Institute in Baltimore, is involved in this project.
She spoke for all of us when she said, “Webb’s new images are extraordinary. 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.”
The galaxies mentioned here are spiral galaxies similar to our own Milky Way. Their massive arms define them, and they are more like traveling waves through space than individual stars moving collectively. Astronomers study these spiral arms to understand how galaxies build, maintain, and shut off star formation. These structures follow a similar pattern in certain parts of the galaxies, and their spacing provides insight into how a galaxy distributes its gas and dust.
The James Webb Space Telescope (JWST), since the beginning of its science operations, has provided astronomers with an overwhelming flow of data that will aid research for years and decades to come. The beautiful images shown here are just a small part of a larger data release that includes a catalog of about 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,” said the University of Alberta’s Erik Rosolowsky. “We’re excited to support the community so all researchers can contribute.”