Astronomers have assembled one of the most comprehensive portraits yet of the Universe’s evolutionary history.
Hubble’s ultraviolet vision opens a new window on the evolving Universe, tracking the birth of stars over the last 11 billion years back to the cosmos’ busiest star-forming period, about 3 billion years after the Big Bang. This new image from Hubble encompasses a sea of approximately 15,000 galaxies — 12,000 of which are starburst galaxies — widely distributed in time and space. Image credit: NASA / ESA / P. Oesch, University of Geneva / M. Montes, University of New South Wales.
The Hubble Deep Field from 1995 allowed astronomers a first glimpse into the early Universe. This first picture was followed later by an even deeper observation, the Hubble Ultra Deep Field in 2004.
Both images were observed in visible light, the same form of light human eyes can see. But astronomers are also interested in the many forms of invisible light out in the Universe.
Therefore, the Ultra Deep Field was later observed in the infrared and the ultraviolet as well, allowing scientists to learn even more about the Universe and to look back even further into its history.
It is less known that the famous deep field observations were not the only images the NASA/ESA Hubble Space Telescope took of the distant Universe.
Hubble is also an essential part of the Great Observatories Origins Deep Survey (GOODS) program, which unites extremely deep observations from several space telescopes: NASA’s Spitzer and Chandra; ESA’s Herschel and XMM-Newton; and Hubble.
Together these observatories observe two patches of the sky, the GOODS North and the GOODS South fields, with the aim of studying it in as many different wavelengths as possible.
The new Hubble image is a portion of the GOODS-North field, which is located in the northern constellation Ursa Major.
The photo features approximately 15,000 galaxies, about 12,000 of which are star-forming, and is 14 times the area of the Hubble Ultra Violet Ultra Deep Field released in 2014.
It was taken by Dr. Pascal Oesch, an astronomer at Yale University and the University of Geneva, and colleagues as part of the Hubble Deep UV Legacy Survey (HDUV), a 132-orbit imaging program with Hubble’s Wide Field Camera 3 (WFC3) instrument.
“This Hubble image straddles the gap between the very distant galaxies, which can only be viewed in infrared light, and closer galaxies, which can be seen across a broad spectrum,” the astronomers said.
“The light from distant star-forming regions in remote galaxies started out as ultraviolet.”
“However, the expansion of the Universe has shifted the light into infrared wavelengths.”
“By comparing images of star formation in the distant and nearby Universe, we glean a better understanding of how nearby galaxies grew from small clumps of hot, young stars long ago.”
“Because Earth’s atmosphere filters most ultraviolet light, Hubble can provide some of the most sensitive space-based ultraviolet observations possible.”
The team’s results appear in the Astrophysical Journal Supplement Series (arXiv.org preprint).
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P.A. Oesch et al. 2018. HDUV: The Hubble Deep UV Legacy Survey. ApJS 237, 12; doi: 10.3847/1538-4365/aacb30
