The Universe Revealed by Subaru Telescope Ⅴ

The Distant Universe

Observation of a celestial object that is very far away is in reality an observation of that object in the very distant past. The birth of the universe occurred about 14 billion years ago. Subaru Telescope has imaged galaxies 13 billion light-years away, giving us a look at the universe as it was 13 billion years ago. This is the most interesting time in the history of the universe because it was the period in which large clusters of stars the first galaxies were forming.


The Most Distant Galaxy Discovered with Subaru


This galaxy(enlarged picture), at a redshift of 7, was discovered by the use of a new filter attached to the Prime Focus Camera. Using FOCAS (Faint Object Camera and Spectrograph), a spectroscopic analysis of this galaxy was completed. From the emission of hydrogen, this galaxy's redshift-distance was calculated precisely.

The "Subaru Deep Field" project was planned to allow astronomers to look out to the farthest reaches of the universe (Page 2). By making such deep exposures, Subaru Telescope has discovered a galaxy with a redshift of 7, which means that it lies about 12.88 billion light-years away. As of October 2007, it was the most distant galaxy whose distance was measured precisely by the spectroscopic observations. The light it emitted shows the galaxy as it looked only 780 million years after the Big Bang or less than 5 percent of its present age. The number of galaxies that have been observed at this great distance is fewer than predicted, considering the number and distribution of less-distant galaxies. Such a deep-space observation is only now able to resolve this very early period in the history of the universe—a time when galaxies were just being born.



The Most Distant Cluster of Galaxies

In our current view of the universe, clusters of galaxies are places where many are gathered in a small area of space. However, it is still unknown when and how dense clusters originally formed. Through observations using Subaru Prime Focus Camera, a space map covering an area 12.7 billion light-years across has been created. A group of galaxies was discovered (designated by the square in the picture) that turns out to be a newly born galaxy cluster. It is thought to be in the first stages of growth, well on its way to becoming an even larger cluster of galaxies.



Gigantic γ-ray Burst Caused by a Very Distant Object


Afterglow data measured 3-4 days after the γ-ray burst toward GRB050904. Above the graph is the data captured by the detector. The middle section of the graph is the spectrum displayed as light intensity; hydrogen atoms absorb shorter wavelengths. The wavy line is the theory model. The lower portion of the graph shows the spectrum of radiation produced by the earth's atmosphere, which interferes with efficient observations for comparison purposes

In our current view of the universe, clusters of galaxies are places where many are gathered in a small area of space. However, it is still unknown when and how dense clusters originally formed. Through observations using Subaru Prime Focus Camera, a space map covering an area 12.7 billion light-years across has been created. A group of galaxies was discovered (designated by the square in the picture) that turns out to be a newly born galaxy cluster. It is thought to be in the first stages of growth, well on its way to becoming an even larger cluster of galaxies.





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