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Colliding galaxies found with help of a cosmic magnifying lens

The Universe works in spectacular ways, allowing us to see events that have occurred billions and billions of years ago. Forbes reported on Aug. 27, that when the most powerful telescopes have met the extent of their range, gravitational lenses, such as galaxies, can help. The gravitational lenses can bend the light in such a way that events that were before out of Earth’s viewing range become visible. With the aid of such a lens, astronomers have been able to capture the best view they have ever seen of two galaxies colliding.

A view of two merging galaxies by way of looking through a gravitational lens.
A view of two merging galaxies by way of looking through a gravitational lens.
NASA/ESA/ESO/W. M. Keck Observatory

The view of the distant galaxies seems to resemble a more local galaxy collision known as the Antennae Galaxies. The astronomers used many telescopes which were both in space and on the Earth, including the Hubble space telescope and Keck observatory to view the event.

Using gravitational lenses is nothing new. Astronomers use them to boost their ability to see billions-of-years-old astronomical events. The use of such lenses was a prediction made by Albert Einstein’s theory of general relativity. Black holes, stars and other phenomena can also be used as gravitational lenses. The first of the known gravitational lenses used by astronomers was discovered in 1998 via the Hubble Space Telescope.

In order for the lens to work, observers must be in line with the object in space being viewed and the lens, as well. "These chance alignments are quite rare and tend to be hard to identify," stated Hugo Messias of the Universidad de Concepción (Chile) and the Centro de Astronomia e Astrofísica da Universidade de Lisboa (Portugal), "but, recent studies have shown that by observing at far-infrared and millimetre wavelengths we can find these cases much more efficiently." To find out more about how gravitational lenses work, you can read more here.

The galaxy viewed is reported to be one of the “brightest gravitationally lensed objects” found so far. And astronomers are excited that they have been able to see details from the collision. One of the members of this particular team, R.J. Ivison, stated it was with teamwork and the collaborative efforts of many telescopes that the event was able to be seen and its appropriate alignment to be found. He told the press that they were able “to take advantage of the foreground galaxy’s lensing effects and characterise the properties of this distant merger and the extreme starburst within it.” Not bad for tracking something billions and billions of years away!