Light from the distant supernova-hosting galaxy was gravitationally lensed by the foreground galaxy cluster RX J2129.6+0005 (RX J2129 for short).
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.
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 massive galaxy cluster, its path is changed slightly.
Called gravitational lensing, this effect is only visible in rare cases and only world’s best telescopes can observe the related phenomena.
“Gravitational lensing occurs when a massive celestial body causes a sufficient curvature of spacetime to bend the path of light traveling past or through it, almost like a vast lens,” Webb astronomers said.
“In this case, the lens is the galaxy cluster RX J2129, located around 3.2 billion light-years from Earth in the constellation of Aquarius.”
“Gravitational lensing can cause background objects to appear strangely distorted, as can be seen by the concentric arcs of light in the upper right of the Webb image.”
The astronomers discovered a supernova called AT 2022riv in the triply-lensed background galaxy using observations from the NASA/ESA Hubble Space Telescope, and they suspected that they had found a very distant Type Ia supernova.
Type Ia supernovae always produce a fairly consistent luminosity — at the same distance, one looks as bright as any other — which makes them particularly helpful to astronomers.
As their distance from Earth is proportional to how dim they appear in the night sky, objects with known brightness can be used as ‘standard candles’ to measure astronomical distances.
The almost uniform luminosity of a Type Ia supernova could also allow astronomers to understand how strongly the galaxy cluster RX J2129 is magnifying background objects, and therefore…
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