The proximity of four of the five Stefan galaxies to each other (the fifth only seems close) allows astronomers to ignite galactic mergers and intergalactic reactions. And also how black holes affect the flow of matter between galaxies

Stefan's Quintet, a visual group of five galaxies, is best known for its prominent appearance in the classic film It's a Wonderful Life. Today, NASA's James Webb Space Telescope reveals the Stefan quintet in new light. This enormous mosaic is Webb's largest imaging to date, covering an angular area roughly one-fifth the diameter of the Moon. The image contains over 150 million pixels and is made up of nearly 1,000 image files The information from the Web provides new insights into how galactic interactions might have driven the The evolution of galaxies in the early universe.
Thanks to its powerful infrared vision and highest spatial resolution, Webb shows details never before seen in this group of galaxies. Sparkling clusters of millions of young stars and regions of fresh star birth grace the picture. Drifting tails of gas, dust and stars are pulled from some of the galaxies due to gravitational interactions. Most dramatically, Webb was able to photograph huge shock waves that form when one of the galaxies, NGC 7318B, smashes through the cluster.
Together, the five galaxies of the Stefan Quintet are also known as the Hexon Compact Group 92 (HCG 92). Although they are called the "quintet", only four of the galaxies are really close together and caught in a cosmic dance. The fifth and leftmost galaxy, called NGC 7320, is in the foreground compared to the other four. NGC 7320 lies 40 million light-years from Earth, while the other four galaxies (NGC 7317, NGC 7318A, NGC 7318B, and NGC 7319) are about 290 million light-years away. That's still pretty close in cosmic terms, compared to galaxies billions of light years away. Studying relatively nearby galaxies such as these helps scientists better understand structures that are often seen in the much more distant universe.
This proximity provides astronomers with a good vantage point to witness the mergers and interactions between galaxies that are so essential to all galaxy evolution. Rarely do scientists see in such detail how galaxies interact and cause stars to form with one another, and how the gas in those galaxies is disrupted. The Stefan quintet is a fantastic "laboratory" for studying these fundamental processes for all galaxies.
Such tight groups may have been more common in the early universe, when their heated matter and mutual attraction may have fueled highly energetic black holes called quasars. Even today, the leading galaxy in the group – NGC 7319 – contains An active galactic nucleus, a supermassive black hole with a mass 24 million times the mass of the Sun. It actively attracts matter and emits light energy equivalent to 40 billion suns.
The Webb Telescope has studied the active galactic nucleus in great detail using a near-infrared spectrograph (NIRSpec) and a mid-infrared device (MIRI). The integral field units (IFUs) of these devices - which are a combination of a camera and spectrograph – Provided the Webb team with a "data cube", consisting of a collection of images of the spectral features of the galactic core.
Similar to medical magnetic resonance imaging (MRI), the IFUs allow scientists to "slice and chop" the information into many images for detailed study. Webb penetrates the dust mantle surrounding the nucleus to reveal hot gas near the active black hole and measure the speed of the bright streams. The telescope saw these jets being driven by the black hole at a level of detail never seen before.
In NGC 7320, the leftmost and closest galaxy in the visual cluster (meaning not gravitationally bound to the others), Webb was able to detect individual stars and even the galaxy's bright core.
As a bonus, Webb revealed a vast sea of thousands of distant background galaxies reminiscent of Hubble's deep fields.
Combined with the most detailed infrared image ever of the Stefan quintet from MIRI and the Near Infrared Camera (NIR Cam), the Web data will provide a wealth of new and valuable information. For example, this photograph will help scientists understand the rate at which supermassive black holes feed and grow. Webb also sees star-forming regions much more directly, and is able to examine the emission from the dust - a level of detail that has not been possible before.
The Stephane Quintet, located in the constellation Pegasus, was discovered by the French astronomer Edouard Stephane in 1877.
Image credit: NASA, ESA, CSA and STScI
To the article on the NASA website
- Webb reveals in detail the steamy atmosphere of a distant planet
- Webb sheds light on the evolution of galaxies and black holes in Stefan's quintet
- NASA's Webb Telescope reveals cosmic cliffs and star-forming regions in the Carina Nebula
- The Webb Space Telescope photographed the Southern Ring Nebula: the last show of an exploding star
- The first official photograph of the Webb Space Telescope: the highest resolution image of a deep space field