Surprisingly, this is not two galaxies at all, but one, its name is SGAS J143845 + 145407. It seems that they are only two, thanks to the way the gravity of a massive object (or things, like a group of galaxies) warps the space through which distant light travels.
Imagine putting a heavy weight on the trampoline, where the weight represents the mass of galaxies, and the trampoline mat represents spacetime. Now roll some balls from one side of the trampoline to the other. Its ordinary “straight” paths will appear to bend along different paths, not unlike rays of light through distorted space.
This gravitational deflection, called a gravitational lensing, can be used to magnify the light of background galaxies that would be too far away to be seen in much detail, as shown in the graph below.
So gravitational lenses like these could be an important tool for understanding the distant universe.
Sometimes this light can distort and distort, as seen in a recent deep field image from the James Webb Space Telescope. Those wobbly, worm-like strange objects are lenticular galaxies. When the lens effect results in four images of a distant object lined up around the central lens block, this is called an Einstein cross.
SGAS J143845 + 145407 appears at the correct point behind a small galaxy cluster of gravitational lenses to produce two near-perfect images of the galaxy, with the added advantage of making them appear larger in greater detail.
Light from SGAS J143845 + 145407 has traveled about 6.9 billion years to reach us. This is about half the life of the current universe. The cluster’s light traveled about 2.8 billion years.
SGAS J143845 + 145407 is scientifically interesting because it is an infrared luminous galaxy, glowing relatively brightly due to the high activity of star formation. Studying galaxies like hers can help scientists understand the formation of stars and how it has changed throughout the history of the universe. For this type of work, gravity lenses can be invaluable.
Using a gravitational lens, scientists were recently able to reconstruct the distribution of star formation at SGAS J143845 + 145407, and study the details of the process. They found that the galaxy is largely typical of its kind, that is, information that will be able to help contextualize and characterize other galaxies.
Webb is expected to reveal more details, but Hubble has revolutionized the study of lenticular galaxies. His observations were the first to resolve details within lenticular galaxies, giving scientists a startling new window into the early universe.
The image was posted on the Hubble website.