Astrophysicists use a naturally-occurring phenomenon to see the object

Feb 15, 2012 10:48 GMT  ·  By
RCSGA 032727-132609 seen through the gravitational lensing effect of an interposing galactic cluster
   RCSGA 032727-132609 seen through the gravitational lensing effect of an interposing galactic cluster

Investigators at the University of Michigan recently used the galaxy cluster RCS2 032727-132623 as a giant space lens for observing the extremely distant galaxy called RCSGA 032727-132609. The experts relied on a phenomenon called gravitational lensing to conduct this study.

In short, gravitational lensing is a process through which light gets bent under intense gravitational pulls. In space, it occurs when a galaxy or other large cosmic object is interposed between Earth and a distant galaxy in the background.

Light emitted by the distant structure cannot reach Earth directly, on account of the interference. Instead, it gets bent around the edges of the galaxy in between. This means that the interposed object acts like a giant lens in space, allowing us to see far behind it with high levels of detail.

Using the NASA/ESA Hubble Space Telescope, U-M astronomers were able to collect high-resolution images of RCSGA 032727-132609, which appears as a nearly 90-degree arc of light in the night sky.

The structure is one of the brightest distant galaxies known. “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,” scientist Keren Sharon explains.

She is the first author of a new paper describing the study, entitled “Source Plane Reconstruction of The Bright Lensed Galaxy RCSGA 032727-132609.” The work appears in the latest online issue of the esteemed Astrophysical Journal.

Sharon, a visiting scholar at the University of Michigan since 2009, adds that parts of the distant galaxy are amplified hundreds of times by the interposing cluster. Gravitational lensing is a very powerful tool in astronomy, especially when it comes to studying extremely distant and young galaxies.

Using the Hubble photo as a starting point, Sharon and the U-M group began reconstructing the actual shape of RCSGA 032727-132609, by applying a series of equations to each individual pixel in the image.

“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 explains.

“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,” she concludes.