Webb Space Telescope captures Stephan’s Quintet in a mosaic with nearly 1,000 images
posted Friday, July 15, 2022 at 3:00 PM EDT
Yesterday, we looked at Webb's incredible photos of the Southern Ring Nebula. On Wednesday, the focus was Webb's first deep field image of SMACS 0723, the sharpest and deepest image of the universe captured so far. Now it's time to look at Stephan's Quintet, as imaged by Webb's Near-Infrared Camera (NIRCam) and Mid-Infrared Instrument (MIRI).
The Stephan's Quintet image is an enormous mosaic of nearly 1,000 images. It's Webb's large image to date and contains over 150 million pixels. You can download the full 150MB .TIFF file here. All that detail lets researchers investigate how interactions between galaxies drive galaxy evolution in the early universe.
The "quintet" in Stephan's Quintet are five galaxies. They're also known as the Hickson Compact Group 92 (HGC 92). Stephan's Quintet was discovered in 1877 by the French astronomer Édouard Stephan in 1877, and it's located in the constellation Pegasus.
While there are five galaxies, only four of them are "caught up in a cosmic dance." Even though the five galaxies appear close to each other, the fifth, and leftmost galaxy, NGC 7320, is pretty far (but still sort of close in cosmic terms) from the other four galaxies. NGC 7320 is about 40 million light-years from Earth, whereas the other galaxies, NGC 7317, NGC 7318A, NGC 7318B, and NGC 7319, are about 290 million light-years away.
Stephan's Quintet is an amazing "laboratory" to study how galaxies merging and interacting affect galactic evolution. "Rarely do scientists see in so much detail how interacting galaxies trigger star formation in each other and how the gas in these galaxies is being disturbed. Stephan’s Quintet is a fantastic 'laboratory' for studying these processes fundamental to all galaxies," NASA writes.
Tight galactic groupings may have been more common during the early universe because superheated, infalling material "may have fueled very energetic black holes called quasars." The topmost galaxy in Stephan's Quintet, NGC 7319, includes an active galactic nucleus, which is a supermassive black hole about 24 million times the mass of the Sun. The supermassive black hole pulls in materials and produces light energy equivalent to about 40 billion Suns. Talk about powerful.
Webb took a closer look at the active galactic nucleus using its Near-Infrared Spectrograph (NIRSpec) and Mid-Infrared Instrument (MIRI). These instruments include integral field units (IFUs), which include a camera and spectrograph. The instruments provide the Webb team with a "data cube," a "collection of images of the galactic core's spectral features." NASA writes, "Much like medical magnetic resonance imaging (MRI), the IFUs allow scientists to 'slice and dice' the information into many images for detailed study. Webb pierced through the shroud of dust surrounding the nucleus to reveal hot gas near the active black hole and measure the velocity of bright outflows. The telescope saw these outflows driven by the black hole in a level of detail never seen before.
It's also important to put the new image of Stephan's Quintet into context. The Hubble Space Telescope captured a beautiful image of Stephan's Quintet back in 2009. You can see the image below and read more about it by clicking here.
There's no doubt that Webb provides a significant resolution boost over Hubble. NASA writes, "Combined with the most detailed infrared image ever of Stephan’s Quintet from MIRI and the Near-Infrared Camera (NIRCam), the data from Webb will provide a bounty of valuable, new information. For example, it will help scientists understand the rate at which supermassive black holes feed and grow. Webb also sees star-forming regions much more directly, and it is able to examine emission from the dust – a level of detail impossible to obtain until now."