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curiousuburb
Antimatter Man
 
Join Date: May 2004
Location: that interweb thing
 
2012-09-26, 09:51

First there was the Hubble Deep Field... then there was the Ultra Deep Field... now behold the eXtreme Deep Field.



Click images for alternate sizes and top link for video explanation


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Like photographers assembling a portfolio of best shots, astronomers have assembled a new, improved portrait of mankind's deepest-ever view of the universe.

Called the eXtreme Deep Field, or XDF, the photo was assembled by combining 10 years of NASA Hubble Space Telescope photographs taken of a patch of sky at the center of the original Hubble Ultra Deep Field. The XDF is a small fraction of the angular diameter of the full Moon.

The Hubble Ultra Deep Field is an image of a small area of space in the constellation Fornax, created using Hubble Space Telescope data from 2003 and 2004. By collecting faint light over many hours of observation, it revealed thousands of galaxies, both nearby and very distant, making it the deepest image of the universe ever taken at that time.

The new full-color XDF image reaches much fainter galaxies, and includes very deep exposures in red light from Hubble's new infrared camera, enabling new studies of the earliest galaxies in the universe. The XDF contains about 5,500 galaxies even within its smaller field of view. The faintest galaxies are one ten-billionth the brightness of what the human eye can see.

Magnificent spiral galaxies similar in shape to our Milky Way and the neighboring Andromeda galaxy appear in this image, as do the large, fuzzy red galaxies where the formation of new stars has ceased. These red galaxies are the remnants of dramatic collisions between galaxies and are in their declining years. Peppered across the field are tiny, faint, more distant galaxies that were like the seedlings from which today's striking galaxies grew. The history of galaxies — from soon after the first galaxies were born to the great galaxies of today, like our Milky Way — is laid out in this one remarkable image.

Hubble pointed at a tiny patch of southern sky in repeat visits (made over the past decade) for a total of 50 days, with a total exposure time of 2 million seconds. More than 2,000 images of the same field were taken with Hubble's two premier cameras — the Advanced Camera for Surveys and the Wide Field Camera 3, which extends Hubble's vision into near-infrared light — and combined to make the XDF.

"The XDF is the deepest image of the sky ever obtained and reveals the faintest and most distant galaxies ever seen. XDF allows us to explore further back in time than ever before," said Garth Illingworth of the University of California at Santa Cruz, principal investigator of the Hubble Ultra Deep Field 2009 (HUDF09) program.

The universe is 13.7 billion years old, and the XDF reveals galaxies that span back 13.2 billion years in time. Most of the galaxies in the XDF are seen when they were young, small, and growing, often violently as they collided and merged together. The early universe was a time of dramatic birth for galaxies containing brilliant blue stars extraordinarily brighter than our Sun. The light from those past events is just arriving at Earth now, and so the XDF is a "time tunnel into the distant past." The youngest galaxy found in the XDF existed just 450 million years after the universe's birth in the big bang.
... continues ...

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This image compares the angular size of the XDF field to the angular size of the full Moon. The XDF is a very small fraction of sky area, but it provides a "core sample" of the heavens by penetrating deep into space over a sightline of over 13 billion light-years. Several thousand galaxies are contained within this small field of view. At an angular diameter of one-half degree, the Moon spans an area of sky only one-half the width of a finger held at arm's length.

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This illustration separates the XDF into three planes showing foreground, background, and very far background galaxies. These divisions reflect different epochs in the evolving universe. Fully mature galaxies are in the foreground plane that shows galaxies as they looked less than 5 billion years ago. The universe is rich in evolving, nearly mature galaxies from 5 to 9 billion years ago. Beyond 9 billion years the universe is awash in compact galaxies and proto-galaxies, blazing with young stars.
[/Boggles][/Mind]

Last edited by curiousuburb : 2012-09-26 at 10:12. Reason: Trying to get reasonably sized images
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