The James Webb Space Telescope—a $10 billion observatory that sees beyond human vision and into the infrared—has sent back more images of galaxies in unprecedented resolution.
The images are the subject of a special issue of journal The Astrophysical Journal Letters this week that features a whopping 21 research papers that together tease-out new details about the beginnings of star formation and how that affects the evolution of huge galaxies.
The images were all taken using JWST’s MIRI (Mid-Infrared Instrument), a camera and a spectrograph that sees light in the mid-infrared region of the electromagnetic spectrum and takes better-than-Hubble wide-field astrophotography images.
JWST’s ability to see in infrared means it can look through dust clouds that block visible light reaching telescopes like Hubble. However, as this image (above) of the “Phantom Galaxy” shows, JWST is also proving a huge step forward when compared to its predecessor, the infrared-capable Spitzer Space Telescope, which was live between 2003 and 2020. The galaxy is about 32 million light-years distant in the constellation of Pisces.
“Since Spitzer was retired, we haven’t had much access to the mid-infrared spectrum, but JWST is incredible,” said Karin Sandstrom, Associate Professor of Physics at University of California San Diego and co-author of one of the new papers, on the interstellar medium (the gas and dust between galaxies). Spitzer had a mirror that was 0.8 meters whereas JWST’s mirror is 6.5 meters. “It’s a huge telescope and it has amazing instruments,” said Sandstrom. “I’ve been waiting a very long time for this.”
The new details displayed in these images are spectacular and scientifically important.
NGC 1433, pictured above, is a barred spiral galaxy with a bright core surrounded by two rings that are each producing stars. JWST’s infrared images—translated into visible color using filters—include bubbles of gas where stars have released energy into their surrounding environment in their birth-throes.
NGC 1433 is about 46 million light-years distant in the southern hemisphere constellation of Horologium and known as a Seyfert galaxy because of its active nuclei.
It’s hoped that images like this can help researchers map the structure of molecular clouds that stars form from as well as the gas surrounding baby stars to get to the bottom of how a galaxy forms new stars.
“Areas which are completely dark in Hubble imaging light up in exquisite detail in these new infrared images, allowing us to study how the dust in the interstellar medium has absorbed the light from forming stars and emitted it back out in the infrared, illuminating an intricate network of gas and dust,” said Sandstrom.
Another image published this week—though actually the first spiral galaxy JWST looked at when its science phase began in mid-2022—is of NGC 7496. A spiral galaxy about 24 million light-years away in the constellation of Grus, it’s stuffed with star clusters and dust lanes.
In this image, above, its spiral arms are flecked with huge bubbles that are the result of baby stars releasing energy.
In this image (below) of NGC 1365, a double-barred spiral galaxy about 56 million light-years away in the constellation Fornax, clumps of dust and gas in the interstellar medium have absorbed the light from forming stars and emitted it back out in the infrared. For the first time astronomers can see what’s going on inside the galaxy.
All of these stunning images are part of one of the early “Webb Treasury” studies. The long-running Physics at High Angular resolution in Nearby GalaxieS (PHANGS) survey has been building a dataset that investigates the links between stars and cold molecular gas in spiral galaxies, most recently using Hubble, but also the ALMA radio observatory and the Very Large Telescope, both in Chile.
The international research team is now using JWST to survey the stars, star clusters, and dust that lie within 19 nearby galaxies. Five have now taken place—four of which feature here—with 14 more to come.
Wishing you clear skies and wide eyes.