Hubble Ultra Deep Field

The Hubble Ultra Deep Field ( HUDF ) is an image of a small region of the sky, taken by the Hubble Space Telescope over a period of 3 September 2003 to 16 January 2004. It was until the release of the Hubble Extreme Deep Field in September 2012, the deepest image of the universe that has ever been recorded in the range of visible light. Here, a region of the sky has been selected, which contains hardly disturbing bright stars in the foreground. They opted southwest of Orion for a target region in the constellation Chemical oven. It is located at right ascension 3h 32 m 39.0 s and declination -27 ° 47 ' 29.1 ". The diameter of the selected sky section corresponds to the view of the earth about one-tenth of the diameter of the moon. This corresponds to a 1 mm by 1 mm area at a distance of one meter and represents about one thirteen- millionth of the entire visible sky Represents the HUDF contains about 10,000 galaxies and large cosmic objects. It consists of two separate recordings by Hubble's " Advanced Camera for Surveys ' (ACS ) and the " Near Infrared Camera and Multi- Object Spectrometer " ( NICMOS ). The picture was taken from 800 individual exposures that were carried out during 400 orbits Hubble. The total exposure time was 11.3 days for ACS and 4.5 days for NICMOS. In order to observe the entire sky in this resolution, the Hubble Space Telescope would need a million years.

The Hubble Ultra Deep Field in the tradition of the Hubble Deep Field and Hubble Deep Field South, which were taken with the old camera WFPC2, are less deep and cover a smaller field. After installing the WFC3/IR-Kamera the same area of ​​the sky end of August 2009 was recorded in the near infrared at wavelengths of 1.05, 1.25 and 1.6 micrometers as HUDF09 over four days with a total exposure time of 48 hours

Scientific Importance

The HUDF shows the faintest galaxies that have been observed so far, and thus the most distant ( one speaks of the "depth" of the image). Because of the finite speed of light, the light travel time from the most distant galaxies to us is over 13 billion years. According to the standard cosmological model one looks back to the early days of the universe 800 million years after the Big Bang. The picture shows therefore some of the first galaxies, which have emerged from the dark ages so-called. Studies on the formation and evolution of galaxies were the main motivation for the project.

In fact, the HUDF out that as the proportion of irregular galaxies with redshift, ie the distance increases, the average galaxy size decreases it. The star formation rate was significantly higher than it is today at high redshift.

In the interpretation of the observations should be noted that light that we see from distant galaxies in the visible region, has actually been sent out due to the cosmological redshift in the ultraviolet. Visual observations of the morphology of distant galaxies must therefore be compared with the corresponding observations of local galaxies in the ultraviolet. Alternatively, one can observe distant galaxies in the infrared light that was emitted as visible light from the galaxies. Here, the new Spitzer Space Telescope play ( started on August 25, 2003) and in the future the Herschel space telescope (launched on 14 May 2009 ) and the successor to the HST, the James Webb Space Telescope ( planned for end of 2018 ), a role. The latter is designed for observations in the near infrared.

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