A breathtaking, ‘bejeweled’ halo of warped light, generated by a monstrous black hole, takes center stage in one of the latest James Webb Space Telescope (JWST) images. This luminous loop, strikingly similar to a cosmic crown, is adorned by four bright spots, though not all of them are genuine. The star-studded halo in the image is composed of light emanating from a quasar – a supermassive black hole at the heart of a young galaxy that shoots out powerful energy jets as it devours enormous amounts of matter. This quasar, previously known to scientists, is named RX J1131-1231 and is situated around 6 billion light-years from Earth in the constellation Crater, according to the European Space Agency (ESA).
The quasar’s circular shape is the result of a phenomenon called gravitational lensing, where light from a distant object – such as a galaxy, quasar, or supernova – travels through space-time that has been curved by the gravity of another massive object located between the distant object and the observer. Consequently, light appears to bend around the middle object even though it is traveling in a straight line. In this instance, the quasar is being lensed by a closer unnamed galaxy, which is visible as a blue dot in the center of the luminous ring.
Gravitational lensing also magnifies our view of extremely distant objects like RX J1131-1231, which would otherwise be too faint to observe. This magnification effect can create bright spots in lensed objects, which are known as ‘multiple images,’ especially when the distant object is not perfectly aligned with the observer. This photo exhibits four bright spots, suggesting four different objects are being lensed. However, the orientation and appearance of these ‘jewels’ around the ring reveal that they are mirror images of a single bright spot, which has been duplicated by the lensing effect, according to ESA. Bright spot duplication is a common occurrence because these objects are some of the brightest entities in the universe.
When the light from a distant, gravitationally-lensed object forms a perfect circle, it is known as an Einstein ring, a term coined because Albert Einstein first predicted the lensing effect with his theory of general relativity in 1915. However, in this case, the light has not been perfectly lensed, and the ring shape is primarily due to the duplication of the quasar’s bright spot. Previous images of the warped quasar also indicate that the light does not create a perfect circle.
Einstein rings and other gravitationally lensed objects can help unveil hidden information about distant objects. For instance, in 2014, researchers utilized the light from RX J1131-1231 to determine how fast its supermassive black hole was spinning, according to Live Science’s sister site Space.com. The size and shape of gravitationally lensed objects also enable scientists to calculate the mass of their lensing galaxies, like the blue dot in this image. By comparing this value to the galaxy’s emitted light, researchers can calculate how much dark matter – a mysterious type of matter that doesn’t interact with light but interacts gravitationally with normal matter – resides within these galaxies. As a result, these warped light shows might be our most potent tools for unraveling the secrets of dark matter.
