(ORDO NEWS) — Stephen’s Quintet, a fairly well-known visual group of five galaxies, even among the layman. NASA’s James Webb Space Telescope has shown Stefan’s quintet in a new light.
This huge mosaic is Webb’s largest image to date, spanning about a fifth of the Moon’s diameter. It contains over 150 million pixels and is made up of nearly 1,000 individual image files.
The information provided by Webb provides new insight into how galactic interactions may have determined the evolution of galaxies in the early universe.
With powerful infrared imaging and extremely high spatial resolution, Webb reveals never-before-seen details in this group of galaxies.
The image is decorated with sparkling clusters of millions of young stars and stellar flare regions in which new stars are born.
From some galaxies, under the influence of gravitational interaction, tails of gas, dust and stars are pulled out.
Most dramatically, Webb captured huge shockwaves as one of the galaxies, NGC 7318B, crashes into the cluster.
Together, the five galaxies of Stefan’s Quintet are also known as the Hickson Compact Group 92 (HCG 92). Although they are called a “quintet”, only four galaxies are really close to each other and participate in the cosmic dance.
The fifth and leftmost galaxy, called NGC 7320, is far in the foreground compared to the other four. NGC 7320 is 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 more distant galaxies billions of light-years away. Studying relatively nearby galaxies like these helps scientists better understand structures seen in a much more distant universe.
This proximity gives astronomers the opportunity to observe the mergers and interactions of galaxies, which are so important for their entire evolution as a whole.
It is rare for scientists to see in such detail how interacting galaxies provoke star formation in each other, and how the gas in them is perturbed. Stefan’s Quintet is a fantastic “laboratory” for studying these processes.
Close clusters like this may have been more common in the early universe, when their superheated, falling material could fuel highly energetic black holes called quasars.
Even today, the topmost galaxy in the group – NGC 7319 – carries an active galactic nucleus, a supermassive black hole with a mass 24 million times that of the Sun. It actively draws material into itself and emits light energy equivalent to 40 billion suns.
Like medical magnetic resonance imaging (MRI), MFPs allow scientists to slice information into multiple images for detailed examination.
Webb pierced through the cloud of dust surrounding the core to detect hot gas near an active black hole and measure the speed of the bright outflows. The telescope saw these streams driven by the black hole in a level of detail never seen before.
In NGC 7320, the leftmost and closest galaxy in the visual group, Webb was able to make out individual stars and even the bright core of the galaxy.
As a bonus, Webb showed a huge sea of thousands of distant background galaxies, reminiscent of Hubble’s Deep Fields.
Combined with the most detailed infrared image of Stefan’s quintet, obtained with MIRI and a near-infrared camera (NIRCam), Webb’s data will provide many valuable new insights. For example, they will help scientists understand how fast supermassive black holes feed and grow.
Webb also sees star-forming regions much more directly, and is able to study emissions from dust – a level of detail that has not been possible until now.
Stephen’s Quintet, located in the constellation Pegasus, was discovered by the French astronomer Edouard Stephen in 1877.
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