ANN ARBOR, Mich.—A natural zoom lens in space has enabled astronomers to build new high-resolution images of one of the brightest distant galaxies magnified through a phenomenon called “gravitational lensing.”
“I was always fascinated by beautiful images of space, but what makes an image like this so much more exciting is that you can actually see physics in action,” said Keren Sharon, a visiting scholar at the University of Michigan. Sharon is the first author of a paper on the findings published online in Astrophysical Journal.
Gravitational lensing occurs when light from a faraway object travels through space that’s been warped by the gravity of a massive foreground object such as a star, a black hole, or even a galaxy cluster. The curved space acts as a lens—distorting and magnifying the light from the remote object.
The phenomenon helps scientists study how galaxies formed and evolved in an earlier time in the universe. It enables more detailed images of galaxies that are so far away light that left them in their formative stages is just now reaching Earth.
The astronomers used the Hubble Space Telescope to image the lensed galaxy RCSGA 032727-132609, which appears as a nearly 90-degree arc of light, parts of which are magnified several hundred times by a foreground cluster of galaxies.
Sharon and her group reconstructed the true shape of the galaxy based on its funhouse mirror appearance through the gravitational lens.
“When I fold the individual pixels of this image through the right set of equations, I can reconstruct the real appearance of the source. And the amazing thing is, it works. Physics works!” Sharon said.
“With this deep understanding of the galaxy morphology, we can now go ahead and interpret our measurements of its physical properties, and shed some light on the physics of star formation when the universe was one-third of its current age.”
The paper, titled “Source-plane reconstruction of the bright lensed galaxy RCSGA 032727-132609,” will appear in the Feb. 20 print edition of Astrophysical Journal. Jane Rigby, an astrophysicist at NASA's Goddard Space Flight Center, led the Hubble Space Telescope observation.