The lensing galaxy cluster SDSS J1226+2149 has magnified distant galaxies, warping their shapes and creating the bright smears of light spread throughout this image from the NASA/ESA/CSA James Webb Space Telescope.
To the lower right of this Webb image is the lensing cluster SDSS J1226+2149 with a very large and bright elliptical galaxy at its center; thin, reddish, stretched-out arcs surround it; one arc is thick and much brighter; another red galaxy is large and warped, just next to the cluster core. Image credit: NASA / ESA / CSA / Webb / J. Rigby.
Galaxy clusters contain thousands of galaxies of all ages, shapes and sizes.
Typically, they have a mass of about one million billion times the mass of the Sun.
At one point in time galaxy clusters were believed to be the largest structures in the Universe — until they were usurped in the 1980s by the discovery of superclusters, which typically contain dozens of galaxy clusters and groups and span hundreds of millions of light-years.
However, clusters do have one thing to cling on to; superclusters are not held together by gravity, so galaxy clusters still retain the title of the biggest structures in the Universe bound by gravity.
Albert Einstein predicted in his theory of general relativity that massive objects will deform the fabric of space itself. When light passes one of these objects, such as a galaxy cluster, its path is changed slightly.
Known as gravitational lensing, this effect is only visible in rare cases and only the best telescopes can observe the related phenomena.
“One of the consequential effects of gravitational lensing is that it can magnify distant astronomical objects, letting astronomers study objects that would otherwise be too faint or far away,” Webb astronomers said in a statement.
“This useful quirk of gravitational lensing has also been used to reveal some of the most distant galaxies humanity has ever encountered.”
“The long, bright, and distorted arc spreading out near the core is one such example.”
“A distant galaxy known as the Cosmic Seahorse, its brightness is greatly magnified by the gravitational lens, which has enabled astronomers to study star formation there.”
The image of the Cosmic Seahorse and a massive foreground galaxy cluster that magnified it was captured by Webb’s Near Infrared Camera (NIRCam).
Called SDSS J1226+2149, the lensing cluster lies at a distance of around 6.3 billion light-years away in the constellation of Coma Berenices.
By combining Webb’s sensitivity with the magnifying effect of gravitational lensing, the astronomers were able to use this gravitational lens to explore the earliest stages of star formation in distant galaxies.
To do so, they relied on earlier studies by the NASA/ESA Hubble Space Telescope, which provided the ‘prescription’ for this gravitational lens.
“This Webb image shows only one observation from a program designed to probe star formation in distant galaxies,” the astronomers said.
“As well as revealing how quickly stars form and characterising the environments in these galaxies that gave rise to new stars, these observations will demonstrate the capabilities of Webb and provide richly detailed datasets to the astronomical community.”
“We expect Webb’s crystal-clear vision and cutting-edge instruments to provide new insights into star formation in distant, gravitationally lensed galaxies.”
