An international team of astronomers using the Atacama Large Millimeter/submillimeter Array (ALMA), and a number of other space- and ground-based telescopes around the world have obtained the best and clearest views of a collision between two galaxies which took place when the universe was half its current age.
The researchers made use of the galaxy H-ATLAS J142935.3-002836 to reveal invisible details. Fresh studies have revealed that this complex and far away object is a well known local galaxy collision, the antennae galaxies.
Lead author Hugo Messias of the Universidad de Concepción (Chile) and the Centro de Astronomía e Astrofísica da Universidade de Lisboa (Portugal) said, “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. 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 light refracted by a normal lens.”
Such cosmic lenses are created by gigantic structures such as galaxies and galaxy clusters which deflect the light from objects behind them as a result of strong gravity. It is known as gravitational lensing and researchers use the magnifying properties of gravitational lensing to study objects which are otherwise not visible. The researchers compare local galaxies with much more remote ones which came into existence when the universe was considerably younger.
H-ATLAS J142935.3-002836 was discovered in the Herschel Astrophysical Terahertz Large Area Survey. It is very faint but is one of the brightest gravitationally-lensed objects in the far-infrared regime. It is being seen by the astronomers at a time when the Universe was half its current age.