School of Physics & Astronomy

Ancient galactic secrets probed in new Hubble survey

Hubble Survey

Scientists at The University of Nottingham are set to be part of one of the biggest explorations of the early universe ever undertaken with the Hubble Space Telescope.
Dr Omar Almaini (Reader & Associate Prof), Dr Chris Conselice (Reader & Associate Prof) and Dr Boris Häußler (Research Fellow) of the School of Physics and Astronomy are part of an international group of researchers taking part in the project, which will provide the first comprehensive view of the structure and assembly of galaxies in the early universe. The project will gather crucial data on the earliest stages in the formation of galaxies and supermassive black holes, in addition to finding distant supernovae.
The project has been awarded an unprecedented 902 orbits of the Hubble Space Telescope – the largest amount of time ever allocated to an individual research project. The observing time, totaling about three and a half months, will be spread out over the next two to three years.
Using Hubble’s powerful new infrared camera, the Wide Field Camera 3 (WFC3), and the Advanced Camera for Surveys (ACS), the project will examine more than 250,000 distant galaxies. A powerful telescope like Hubble allows astronomers to see back in time as it gathers light that has traveled for billions of years across the universe. The new survey will observe galaxies as they were nearly 13 billion years ago (about 600,000 years after the Big Bang) up to about 9 billion years ago.
The new data will be used to answer many key questions about galaxy evolution and cosmology. By studying how galaxy masses, morphologies, and star formation rates changed over time, researchers can test theories of galaxy formation and evolution. Examining supermassive black holes found at the centre of galaxies will be a key part of the survey, as new data could reveal their role in galaxy evolution.
“Here in Nottingham we have been working on these problems for many years, trying to piece together how galaxies have formed over the last 13 billion years,” said Dr Almaini. “Hubble’s new camera will add a vital new ingredient.”
“While before we could only see a faint smudge from our telescopes on the ground, Hubble will bring these distant objects into sharp focus for the first time. This will provide a wealth of new information, to help us understand how galaxies form in the very early universe."
“I will be carrying out an analysis of the resolved structures of the galaxies which will be imaged in this survey,” added Dr Conselice. “This is important because this survey will give us the first optical view of galaxies in the distant universe at high resolution, and thus we can see how the stellar mass in these galaxies is distributed.
“This can reveal how these galaxies are forming through physical processes such as the mergers between galaxies which can form more massive galaxies, as well as trigger the formation of new stars and the black holes in the centres of these galaxies.”
“The project is unique” added Dr Häußler, “since it will survey an enormous volume of the distant Universe but also with sufficiently long exposure to study the galaxies in great detail. We have never before had such a rich set of data to look forward to.”
The project will also search for distant examples of a particular type of exploding star known as a Type Ia supernova. Astronomers have used the uniform brightness of these supernovae to measure cosmic distances, leading to the conclusion that a mysterious force called dark energy is accelerating the expansion of the universe. Observations of distant Type Ia supernovae will enable researchers to study how the rate of expansion of the universe has changed over time.
The project is led by Sandra Faber, Professor of Astronomy and Physics at the University of California, Santa Cruz.
"The earliest galaxies we see are truly infant galaxies. We want to know when massive galaxies first appeared, and when they started to look like the beautiful spiral galaxies we see today," Prof Faber said. "This study will allow us to chart for the first time the maturation process of galaxies."
The first data from the project observations are expected by the end of the year. Data from this project will be made available to the entire astronomy community with no proprietary period for Prof Faber's team to conduct their own analysis.
Additional information about the project is available on the Cosmology Survey Multi-Cycle Treasury Program web site at .

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Posted on Wednesday 17th March 2010

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