Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Vanderbilt astronomers participate in new search for dark energy

06.10.2009
The most ambitious attempt yet to trace the history of the universe has seen "first light." The Baryon Oscillation Spectroscopic Survey (BOSS), part of the Sloan Digital Sky Survey III (SDSS-III), took its first astronomical data on the night of Sept. 14-15 at the Sloan Foundation telescope in New Mexico.

The goal of the six-year project is to measure the spectra of 1.4 million galaxies and 160,000 quasars, extremely distant objects that shine more brightly than entire galaxies.

The previous sky survey (SDSS-II) determined the two-dimensional position of these objects in the sky. The new project will measure their distance, allowing astronomers to produce a three-dimensional map with unprecedented detail that extends out about one-fifth of the full depth of the visible universe and traces the evolution of the universe back some 6.5 billion years.

"This will give us a three-dimensional map of a large volume of the universe, which is exactly what we need to learn more about dark energy," said assistant professor Andreas Berlind. He and his colleagues in Vanderbilt's physics and astronomy department – assistant professor Kelly Holley-Bockelmann, associate professor Keivan Stassun and professor David Weintraub – are participating in the survey along with 350 scientists from 41 other institutions.

Dark energy is a type of "negative gravity" that seems to play a role in accelerating the expansion of the universe. Scientists think it makes up about 70 percent of the energy/matter of the universe but its basic nature is a mystery. "One of the most sensitive measures of dark energy that we have found is the large-scale distribution of galaxies," Berlind said.

BOSS uses the same telescope as the original Sloan Digital Sky Survey, but it has been equipped with new, specially built spectrographs. The new instruments can measure the spectra of 1,000 objects at a time and are considerably more sensitive than the original instruments so they can record the spectra of extremely dim objects. "The new spectrographs are much more efficient in infrared light," explained Natalie Roe of Berkeley Lab, the instrument scientist for BOSS. "The light emitted by distant galaxies arrives at Earth as infrared light, so these improved spectrographs are able to look much farther back in time."

The Vanderbilt team brings a unique resource to the project: A set of more than 400 simulated universes. These are computer models of the universe that start at the Big Bang and then virtually evolve to the present following known physical laws. "Other groups have produced individual simulations that are more detailed than ours, but we've gone for greater numbers in order to get a better idea of the amount of variation that is possible," said Berlind.

These virtual universes are being used to test the BOSS data analysis methods and will be necessary to interpret BOSS's measurements of dark energy. Berlind and his colleagues are generating simulated observational data from a number of their virtual universes; this data is run through the BOSS analysis pipeline and the results are compared with the original. "This allows us to catch any systematic errors that might throw the results off," he said.

ABOUT SDSS-III AND BOSS

BOSS is the largest of four surveys in SDSS-III, which includes 350 scientists from 42 institutions. The BOSS design and implementation has been led from the U.S. Department of Energy's Lawrence Berkeley National Laboratory. The optical systems were designed and built at Johns Hopkins University, with new CCD cameras designed and built at Princeton University and the University of California at Santa Cruz/Lick Observatory. The University of Washington contributed new optical fiber systems, and Ohio State University designed and built an upgraded BOSS data-acquisition system. The "fully depleted" 16-megapixel CCDs for the red cameras evolved from Berkeley Lab research and were fabricated in Berkeley Lab's MicroSystems Laboratory (MSL).

Funding for SDSS-III has been provided by the Alfred P. Sloan Foundation, the Participating Institutions, the National Science Foundation and the U.S. Department of Energy. The SDSS-III web site is http://www.sdss3.org/.

SDSS-III is managed by the Astrophysical Research Consortium for the Participating Institutions of the SDSS-III Collaboration, including the University of Arizona, the Brazilian Participation Group, University of Cambridge, University of Florida, the French Participation Group, the German Participation Group, the Michigan State/Notre Dame/JINA Participation Group, Johns Hopkins University, the U.S. Department of Energy's Lawrence Berkeley National Laboratory, Max Planck Institute for Astrophysics, New Mexico State University, New York University, the Ohio State University, the Pennsylvania State University, University of Portsmouth, Princeton University, University of Tokyo, the University of Utah, Vanderbilt University, University of Virginia and the University of Washington.

For more news about Vanderbilt, visit the Vanderbilt News Service homepage on the Internet at www.vanderbilt.edu/News.

[Note: A multimedia version of this story is available on Exploration, Vanderbilt's online research magazine, at http://www.vanderbilt.edu/exploration/stories/skysurvey.html.]

David F. Salisbury | EurekAlert!
Further information:
http://www.vanderbilt.edu

More articles from Physics and Astronomy:

nachricht NASA spacecraft investigate clues in radiation belts
28.03.2017 | NASA/Goddard Space Flight Center

nachricht Researchers create artificial materials atom-by-atom
28.03.2017 | Aalto University

All articles from Physics and Astronomy >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: A Challenging European Research Project to Develop New Tiny Microscopes

The Institute of Semiconductor Technology and the Institute of Physical and Theoretical Chemistry, both members of the Laboratory for Emerging Nanometrology (LENA), at Technische Universität Braunschweig are partners in a new European research project entitled ChipScope, which aims to develop a completely new and extremely small optical microscope capable of observing the interior of living cells in real time. A consortium of 7 partners from 5 countries will tackle this issue with very ambitious objectives during a four-year research program.

To demonstrate the usefulness of this new scientific tool, at the end of the project the developed chip-sized microscope will be used to observe in real-time...

Im Focus: Giant Magnetic Fields in the Universe

Astronomers from Bonn and Tautenburg in Thuringia (Germany) used the 100-m radio telescope at Effelsberg to observe several galaxy clusters. At the edges of these large accumulations of dark matter, stellar systems (galaxies), hot gas, and charged particles, they found magnetic fields that are exceptionally ordered over distances of many million light years. This makes them the most extended magnetic fields in the universe known so far.

The results will be published on March 22 in the journal „Astronomy & Astrophysics“.

Galaxy clusters are the largest gravitationally bound structures in the universe. With a typical extent of about 10 million light years, i.e. 100 times the...

Im Focus: Tracing down linear ubiquitination

Researchers at the Goethe University Frankfurt, together with partners from the University of Tübingen in Germany and Queen Mary University as well as Francis Crick Institute from London (UK) have developed a novel technology to decipher the secret ubiquitin code.

Ubiquitin is a small protein that can be linked to other cellular proteins, thereby controlling and modulating their functions. The attachment occurs in many...

Im Focus: Perovskite edges can be tuned for optoelectronic performance

Layered 2D material improves efficiency for solar cells and LEDs

In the eternal search for next generation high-efficiency solar cells and LEDs, scientists at Los Alamos National Laboratory and their partners are creating...

Im Focus: Polymer-coated silicon nanosheets as alternative to graphene: A perfect team for nanoelectronics

Silicon nanosheets are thin, two-dimensional layers with exceptional optoelectronic properties very similar to those of graphene. Albeit, the nanosheets are less stable. Now researchers at the Technical University of Munich (TUM) have, for the first time ever, produced a composite material combining silicon nanosheets and a polymer that is both UV-resistant and easy to process. This brings the scientists a significant step closer to industrial applications like flexible displays and photosensors.

Silicon nanosheets are thin, two-dimensional layers with exceptional optoelectronic properties very similar to those of graphene. Albeit, the nanosheets are...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

International Land Use Symposium ILUS 2017: Call for Abstracts and Registration open

20.03.2017 | Event News

CONNECT 2017: International congress on connective tissue

14.03.2017 | Event News

ICTM Conference: Turbine Construction between Big Data and Additive Manufacturing

07.03.2017 | Event News

 
Latest News

Transport of molecular motors into cilia

28.03.2017 | Life Sciences

A novel hybrid UAV that may change the way people operate drones

28.03.2017 | Information Technology

NASA spacecraft investigate clues in radiation belts

28.03.2017 | Physics and Astronomy

VideoLinks
B2B-VideoLinks
More VideoLinks >>>