Millions of stars shine in unprecedented image of spiral galaxies obtained by Webb Telescope

(CNN) — The James Webb Space Telescope captured spectacular images of 19 spiral galaxies and the millions of stars located in them, at a level unprecedented for astronomers.

Webb’s unique ability to observe the universe in different wavelengths of infrared light, such as near-infrared and mid-infrared, reveals the stars, gas and dust within the complex structure of each galaxy.

Astronomers believe that about 60% of all galaxies are spiral, and our Solar System is located in one of the galaxy’s spiral arms. Webb’s observations could help astronomers better understand star formation and the evolution of spiral galaxies like ours.

Seen from the front, each galaxy in the new images has spiral arms filled with stars. At the center of every galaxy are old star clusters or supermassive black holes.

The James Webb Space Telescope imaged 19 spiral galaxies in near- and mid-infrared light. Credit: NASA, ESA, CSA, STScI, Janice Lee (STScI), Thomas Williams (Oxford), PHANGS

The observations were carried out within the framework of the PHANGS (Physics at High Angular Resolution in Nearby Galaxies) project. More than 100 astronomers from around the world are participating in the program, which also analyzes data from the Hubble Space Telescope, the MUSE instrument on the European Space Observatory’s Very Large Telescope, and the Atacama Large Millimeter/submillimeter Array in Chile.

Data obtained from different telescopes allows astronomers to make observations at different wavelengths of visible, ultraviolet and radio light. Incorporating Webb’s infrared data may help fill some observational gaps.

“The new Webb images are extraordinary,” Janice Lee, PHANGS member and project scientist for new missions and strategic initiatives at the Space Telescope Science Institute in Baltimore, said in a statement. “They are surprising even to researchers who have studied these same galaxies for decades. The bubbles and filaments are resolved at the smallest scale ever seen, and they tell a story about the cycle of star formation.”

looking inside the spirals

Astronomers used Webb’s Near Infrared Camera to observe millions of stars, which appear bright blue, grouped into clusters and also distributed throughout the arms of 19 galaxies. For its part, the Webb Mid-Infrared Instrument focuses on the bright dust surrounding the stars, as well as red stars shrouded in the gas and dust that fuel stellar evolution.

“This is where we can find the youngest and most massive stars in galaxies,” PHANGS member and professor of physics at the University of Alberta in Edmonton Eric Rosolowsky said in a statement.

This image shows observations of the galaxy NGC 4254 made by the Webb (top left) and Hubble (bottom right) telescopes. Credit: NASA, ESA, CSA, STScI, Janice Lee (STScI), Thomas Williams (Oxford), PHANGS

The spiral arms in Webb’s images are literally hot with orange and red gas. The images will be used to help astronomers determine the distribution of gas and dust in spiral galaxies, as well as explore how galaxies feed and suppress star formation.

“These structures follow similar patterns in some parts of galaxies,” explains Rosolowski. “We think of them as waves, and their distances tell us a lot about how a galaxy distributes its gas and dust.”

The Webb telescope also captured large circular, shell-shaped gaps in the galactic gas and dust that were likely created by exploding stars.

“These holes may have been created by the explosion of one or more stars, which left giant holes in the interstellar material,” Adam LeRoy, a PHANGS member and professor of astronomy at Ohio State University in Columbus, said in a statement.

anatomy of the galaxy

Astronomers believe that galaxies form from the inside out. Star formation begins in the center of the galaxy before spreading out into the spiral arms. This means that a star’s distance from the galaxy’s heart is relative to its age, so younger stars are likely further away from the galaxy core. Clusters of blue stars near the center of each galaxy indicate older stars.

Meanwhile, some galaxies have pink-red spikes near the center.

“This is a clear indication that there may be an active supermassive black hole,” Eva Schinnerer, a scientist at the Max Planck Institute for Astronomy in Heidelberg, Germany and member of PHANGS, said in a statement. “Or, the star clusters toward the center are so bright that they have saturated that area of ​​the image.”

What scientists are most excited about, according to Leroy, is studying the enormous number of stars revealed by Webb’s new images.

“Stars can live for billions or trillions of years,” Leroy said. “By accurately cataloging all types of stars, we can create a more reliable and holistic view of their life cycles.”