NASA/ESA/CSA's James Webb Space Telescope has captured a fascinating observation of the massive galaxy cluster RX J2129. Thanks to gravitational lensing, this observation reveals three different images of the same galaxy that is hosting a supernova. This rare phenomenon occurs when the gravitational pull of a massive object, such as a galaxy cluster, bends and distorts the light of objects behind it. The JWST's powerful capabilities have allowed for this incredible insight into the effects of gravity on the distant universe.
The NASA/ESA/CSA James Webb Space Telescope has made a fascinating observation of the massive galaxy cluster RX J2129, thanks to gravitational lensing. The phenomenon of gravitational lensing occurs when a massive celestial body curves the path of light traveling through it, creating a vast lens-like effect. In this case, the lens is the galaxy cluster RX J2129, situated in the Aquarius constellation, around 3.2 billion light-years from Earth. Due to gravitational lensing, the observation captured three different images of the same supernova-hosting galaxy, which can be seen in closer detail in the image.
Type Ia supernova
Astronomers discovered the distant Type Ia supernova in the triply-lensed background galaxy using observations from the NASA/ESA Hubble Space Telescope. Type Ia supernovae are a type of supernova that have a consistent luminosity, making them particularly useful to astronomers as standard candles to measure astronomical distances. They are the result of the explosion of a white dwarf star, which is a star that has burned up all of its fuel and collapsed under its own weight. When a white dwarf star is in a binary system with another star, it can steal material from its companion, causing its mass to increase. Once the white dwarf reaches a certain mass, it becomes unstable and explodes, creating a Type Ia supernova.
The almost uniform luminosity of the Type Ia supernova could also allow astronomers to understand how massive the galaxy cluster RX J2129 is, as gravitational lenses can cause distant objects to appear much brighter than they would otherwise. By measuring the brightness of the lensed supernova using Webb’s Near-InfraRed Camera, astronomers can determine the strength of the gravitational lens.
NIRSpec spectroscopy of the supernova
As part of the same observation program, NIRSpec spectroscopy of the supernova was also obtained, allowing for a comparison of this distant supernova to Type Ia supernovae in the nearby Universe. This is an important way to verify one of the astronomers’ tried-and-tested methods of measuring vast distances works as expected. The observation provides a unique opportunity to study the effect of gravitational lensing on distant objects and will allow scientists to better understand the structure of the universe.