Science: Widest deep view of sky ever recorded

European Southern Observatory (ESO) Vista telescope captured the treasure of more than 2,00,000 galaxies using infrared light.

The new image of unremarkable patch of sky comes from the UltraVISTA survey and reveals the wide deep view of the sky ever taken.

It is only one part of a huge collection of fully processed images of all the Vista surveys that are now available for ESO to astronomers around the world.

UltraVISTA is a treasure, which is used to study distant galaxies in the early universe as well as for many other science projects.

The telescope was trained on the same patch of sky repeatedly to slowly build up the very dim light of the most distant galaxies.

In total more than six thousand separate exposures with a total effective exposure time of 55 hours, taken through five different colored filters, were combined to create this image.

This image of the UltraVISTA survey is the deepest infrared view of the sky of its size ever taken.

The Vista telescope at ESO's Paranal Observatory in Chile is the world's largest survey telescope and the most powerful infrared survey telescope in existence.

Since it began work in 2009 a majority of its observation time was devoted to public surveys, some covering large parts of the southern skies and some more focused in small areas.

The UltraVISTA survey was dedicated to the space field, it seems almost an empty patch of sky, which has already been extensively studied using other telescopes, including the NASA / ESA Hubble Space Telescope. UltraVISTA is the deepest of the six Vista polls for and reveals the faintest objects.

At first glance, the UltraVISTA image looks unremarkable, a few bright stars and a sprinkling of fainter ones. But in fact almost all of these fainter objects are not stars in the Milky Way, but very distant galaxies, each containing billions of stars.

Enlarging the image to fill the screen, and zoom in reveals more and more of them, and the image recorded more than 200 000 galaxies in total.

The expansion of the universe changes the light of distant objects to longer wavelengths.

By starlight coming from the most distant galaxies we can see, this means that most of the light falls in the infrared part of the spectrum when it comes to the Earth.

As a very sensitive infrared telescope with a wide field of view, Vista is a uniquely powerful for spotting distant galaxies in the early universe.

By studying galaxies in redshifted light at successively larger distances, astronomers can also track how galaxies were built up and evolved through the history of the cosmos.

Close inspection of the picture shows tens of thousands of previously unknown reddish objects scattered among the more numerous cream-colored galaxies.

These are mostly very distant galaxies seen when the Universe was only a small fraction of its present age. Early studies of the UltraVISTA images, combined with images from other telescopes, revealed the presence of many galaxies that are seen when the Universe was less than a billion years, and some see the evening early age.

Although the current UltraVISTA image is already the deepest infrared image of its size in existence observations are continuous. The end result, a few years from now, will be significantly more so.

Science

Thursday, March 22, 2012

Widest deep view of sky ever recorded

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