Astronomers say they been granted an unprecedented look into the inner structure of a galaxy so far away it sits at the very edge of the knowable, observable universe.
The images of the galaxy known as SDP.81 is courtesy of the Atacama Large Millimeter/submillimeter Array (ALMA), located on a mountaintop in the Atacama desert in northern Chile, which was given a helping hand — a "natural telescope" known as a gravitational lens.
Gravitation lensing occurs when the mass of a large cosmic object — a galaxy, say — causes the light from a more distant object directly behind it to be bent around, making the farther object visible.
Albert Einstein, in his theory of General Relativity, predicted that the gravity of massive objects could bend both space and time, and that light would follow this curvature in space, causing massive objects situated directly between us and an object we might wish to observe to work like an enormous magnifying lens.
The effect can make a distant object appear larger and brighter, and astronomers have used the lensing effect to study galaxies, black holes and dark matter in the distant universe.
In the current study, researchers from the University of Tokyo modeled the lensing effects and corrected them to reveal the distribution of huge star-forming stellar "nurseries" in the monstrous SDP.81 galaxy.
As an unexpected bonus, the observations also revealed the existence of a super-massive black hole in the center of the nearer light-bending galaxy, the researchers are reporting in the journal Publications of the Astronomical Society of Japan.
A high-resolution instrument on ALMA captured the image of SDP.81, 11.7 billion light years from Earth in the constellation Hydra.
Its magnified image is courtesy of the lensing effect of a much nearer galaxy just 3.5 billion light years away, the researchers say.
The image confirms that SDP.81 is enormous and is forming stars at a rate hundreds of thousands of times than seen in our home Milky Way Galaxy.
The ALMA image is so sharp, it revealed branches, bends, small granular structures and other details of the inner structure of the distant, giant galaxy, the researchers said.
"This discovery is an important step to understand the evolutionary process of starburst galaxies and supermassive black holes in galaxies," the study authors wrote.
