Astronomers have produced the largest, most comprehensive ‘history book’ of galaxies in the Universe, using 16 years’ worth of observations from the NASA/ESA Hubble Space Telescope. The ambitious endeavor is called the Hubble Legacy Field. The image, a combination of nearly 7,500 separate Hubble exposures, contains roughly 265,000 galaxies. They stretch back through 13.3 billion years of time to just 500 million years after the Universe’s birth in the Big Bang.
Astronomers developed a mosaic of the distant Universe — called the Hubble Legacy Field — that documents 16 years of observations from the NASA/ESA Hubble Space Telescope. The image contains nearly 265,000 galaxies that stretch back through 13.3 billion years of time to just 500 million years after the Big Bang. The new set of Hubble images, created from nearly 7,500 individual exposures, is the first in a series of Hubble Legacy Field images. Image credit: NASA / ESA / G. Illingworth & D. Magee, University of California, Santa Cruz / K. Whitaker, University of Connecticut / R. Bouwens, Leiden University / P. Oesch, University of Geneva / Hubble Legacy Field Team.
The Hubble Legacy Field combines observations taken by several Hubble deep-field surveys.
In 1995, the Hubble Deep Field captured several thousand previously unseen galaxies.
The subsequent Hubble Ultra Deep Field from 2004 revealed nearly 10,000 galaxies in a single image.
The 2012 Hubble eXtreme Deep Field was assembled by combining ten years of Hubble observations taken of a patch of sky within the original Hubble Ultra Deep Field.
The new set of Hubble images, created from nearly 7,500 individual exposures, is the first in a series of Hubble Legacy Field images.
“Now that we have gone wider than in previous surveys, we are harvesting many more distant galaxies in the largest such dataset ever produced by Hubble,” said Dr. Garth Illingworth, anastronomer at the University of California, Santa Cruz.
“This one image contains the full history of the growth of galaxies in the Universe, from their time as ‘infants’ to when they grew into fully-fledged ‘adults’.”
This graphic reveals close-up images of 15 galaxies from the 265,000 galaxies in the Hubble Legacy Field. Image credit: NASA / ESA / G. Illingworth & D. Magee, University of California, Santa Cruz / K. Whitaker, University of Connecticut / R. Bouwens, Leiden University / P. Oesch, University of Geneva / Hubble Legacy Field Team.
No image will surpass this one until future space telescopes like the NASA/ESA James Webb Space Telescope are launched.
“We’ve put together this mosaic as a tool to be used by us and by other astronomers,” Dr. Illingworth said.
“The expectation is that this survey will lead to an even more coherent, in-depth, and greater understanding of the Universe’s evolution in the coming years.”
The Hubble Legacy Field image yields a huge catalog of distant galaxies.
“Such exquisite high-resolution measurements of the numerous galaxies in this catalog enable a wide swath of extragalactic study,” said Dr. Katherine Whitaker, an astronomer at the University of Connecticut, in Storrs.
“Often, these kinds of surveys have yielded unanticipated discoveries which have had the greatest impact on our understanding of galaxy evolution.”
“One exciting aspect of these new images is the large number of sensitive color channels now available to view distant galaxies, especially in the ultraviolet part of the spectrum,” said Dr. Rychard Bouwens, an astronomer at Leiden University in the Netherlands.
“With images at so many frequencies, we can dissect the light from galaxies into the contributions from old and young stars, as well as active galactic nuclei.”
