Peering Through 'Galactic Lens' Researchers Discover Two Distant Colliding Galaxies From the Universe’s Distant Past
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Earlier this month, with the discovery of two colliding galaxies, an international group of astronomers found that there is far more than meets the eye. In fact, the team found that one of Albert Einstein's posits in his general theory of relativity not only has real world applications, but can help us see deeper in time and space.
The discovery of the colliding galaxies, named "HATLAS J142935.3-002836", was by no means an easy feat. As the collision took place roughly 6.9 billion years ago, when the universe was only half its age, the cosmic event is far beyond the reach of event the most powerful telescopes on Earth or in space. To address the issue, lead researcher Hugo Messias of the Center for Astronomy and Astrophysics, at the University of Lisbon, Portugal decided to think outside of the box and make a theoretical notion a reality.
"While astronomers are often limited by the power of their telescopes, in some cases our ability to see detail is hugely boosted by natural lenses created by the Universe" Messias says. "Einstein predicted in his theory of General Relativity that, given enough mass, light does not travel in a straight line but will be bent in a similar way to a normal lens."
Called a gravitational lens, the use of another supermass in between Earth and the object we're trying to view, the large supergalaxy Messias found in the Herschel Astrophysical Terahertz Large Area Survery (HATLAS) bends the light of the distant cosmic event and acts as an intergalactic magnifying glass of sorts, compounding the images from deep in space to Earth's major telescopes. Becoming a more common method of viewing cosmic events from the Universe's ancient past, gravitational lensing is a very particular form of science that only works if every detail is in perfect cosmic alignment, something researchers here on Earth have no influence on.
"These chance alignments are quite rare and tent to be hard to identify" Messias says. "But, recent studies have shown that by observing at far-infrared and millimeter wavelengths, we can find these cases much more efficiently."
Once Messias was able to spot the chance event, an international team of astronomers were able to confirm the sighting using the Hubble, ALMA, Keck Observatory, the VLA and a group of other international and space-based telescopes, all which view the Universe in slightly different ways.
The first images captured of the galaxy collision were taken by the Hubble and Keck telescopes, revealing that the distant galaxy has an edge-on disc shape, much like our very own Milky Way, and that the galaxies are largely shrouded in dust clouds that hide parts of the collision. Seeking to view past the dust clouds, telescopes VLA and ALMA, which view the Universe at longer wavelengths and do not identify dust, the researchers were able to discovery that the system is actually an ongoing collision between to galaxies, currently forming hundreds of new stars each year.
Co-author and European Southern Observatory's Director for Science, Rob Ivison said "With the combined power of Hubble and these other telescopes we have been able to locate this very fortunate alignment, take advantage of the foreground galaxy's lensing effects and characterize the properties of this distant merger and the extreme starbursts within it."
For more information, visit:
https://sci.esa.int/hubble/54551-best-view-yet-of-merging-galaxies-in-distant-universe-heic1417/
