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"The data from BOSS will be the best ever obtained on the large-scale
structure of the universe," said David Schlegel of the U.S. Department
of Energy's Lawrence Berkeley National Laboratory (Berkeley Lab), the
Principal Investigator of BOSS. BOSS uses the same telescope as the
original Sloan Digital Sky Survey, but equipped with new, specially-
built spectrographs to measure the spectra. The new spectrographs are
much more efficient in infrared light, enabling them to look much
farther back in time.
The ability to look further back in time is important in allowing BOSS
to take advantage of a feature in the universe called "baryon
oscillations." Baryon oscillations began when pressure waves traveled
through the early universe. Like sound waves passing through air, the
waves pushes some of the matter closer together as they travel.
In the early universe, these waves
were moving at half the speed of light, but when the
universe was only a few hundred thousand years old, the universe
cooled enough to halt the waves, leaving a signature 500 million light
years in length.
"We can see these frozen waves in the distribution of galaxies today,"
said Daniel Eisenstein of the University of Arizona, the Director of
the SDSS-III. "By measuring the length of the baryon oscillations, we
can determine how dark energy has affected the expansion history of
the universe. That in turn helps us figure out what dark energy could
be. Studying baryon oscillations is thus an exciting method for
measuring dark energy in a way that's complementary to techniques in
supernova cosmology. BOSS's galaxy measurements will be a
revolutionary dataset that will provide rich insights into the
Universe."
The BOSS spectrographs will work with more than two thousand large
metal plates that are placed at the focal plane of the telescope; these
plates are drilled with the precise locations of nearly two million
objects across the northern sky. Optical fibers plugged into a
thousand tiny holes in each of these "plug plates" carry the light
from each observed galaxy or quasar to BOSS's new spectrographs.
Using these plug plates for the first light image should have been
easy, but it didn't quite turn out the way astronomers planned. "In
our first test images, it looked like we'd just taken random spectra
from all over," Schlegel said. After some hair-pulling, the problem
turned out to be simple. "After we flipped the plus and minus signs in
the program, everything worked perfectly."
"The first light spectra look remarkably good" said Guinevere
Kauffmann, who leads a research group at the Max Planck Institute for
Astrphysics in Germany that has been heavily involved in SDSS for more
than 7 years. "We are very excited about the prospect of being able to
push back in time, towards an epoch when galaxies and their black
holes were much more active than they are today. Small numbers of
spectra of high redshift galaxies are already available, but BOSS
looks set to provide us with a quantum leap over what has gone
before".
The first public data release from SDSS-III is planned for December
2010. The SDSS team has led the way in making high-quality
astronomical data available to all on the Web, with no need to spend
nights awake at a mountaintop telescope. The data continues to
revolutionize astronomical science and education. Original SDSS data
has already been used by others in thousands of research papers.
"This continues the legacy of the SDSS, one of the most productive
astronomical surveys ever undertaken," said Jim Gunn of Princeton
University, who will be awarded this month the National Medal for
Science from President Obama for his pioneering work with the original
SDSS. "The leadership of this next generation of the SDSS has passed
to the young scientists who did most of the hard work in SDSS I and
II, and they have done a wonderful job, quickly and well. Bravo!"
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, University of Portsmouth, Princeton
University, University of Tokyo, the University of Utah, Vanderbilt
University, University of Virginia, University of Washington and Yale
University.
MPA INVOLVEMENT IN BOSS
The Max Planck Institute for Astrophysics (MPA) joined the SDSS consortium
in 2002. SDSS research at MPA has focused on understanding the
physical properties of the local galaxy population, including their
supermassive black holes. MPA scientists pioneered the development of
new analysis techniques for deriving star formation rates,
metallicities, mean stellar ages and black hole accretion rates using
the high quality spectra provided by the survey.
CONTACTS:
In Germany:
Guinevere Kauffmann, SDSS Advisory Council Representative,
Max Planck Institute for Astrophysics,
Phone: +49-89-30000-2014
Email: gamkmpa-garching.mpg.de
Martin Asplund, SDSS Collaboration Council Representative,
Max Planck Institute for Astrophysics,
Phone: +49-89-30000-2208
Email: asplundmpa-garching.mpg.de
Other Countries:
David Schlegel, BOSS Principal Investigator,
Lawrence Berkeley National Laboratory,
Phone: +1 510-495-2595
Email: djschlegellbl.gov
Daniel Eisenstein, SDSS-III Director,
University of Arizona,
Phone: +1 520-621-5904
Email: deisensteinas.arizona.edu
Bob Nichol, SDSS-III Spokesperson,
University of Portsmouth (UK),
Phone: +44 23 9284 3117
Email: bob.nicholport.ac.uk
Paul Preuss, Communications Group,
Lawrence Berkeley National Laboratory,
Phone: +1 510-486-6249
Email: paul_preusslbl.gov
Jordan Raddick, SDSS Public Information Officer,
Johns Hopkins University,
Phone: +1 410-516-8889
Email: raddickjhu.edu
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