Composite Dark Energy Camera image
of one of the sky regions that the collaboration will use to study
supernovae, exploding stars that will help uncover the nature of dark
energy. The outlines of each of the 62 Charged Coupled Devices can be
seen. This picture spans 2 degrees across on the sky and contains 520
megapixels. You can see each individual field in high resolution with
the new DECam interactive feature.
This image of the NGC 1398 galaxy
was taken with the Dark Energy Camera. This galaxy lives in the Fornax
cluster, roughly 65 million light years from Earth. It is 135,000 light
years in diameter, just slightly larger than our own Milky Way galaxy,
and contains more than a hundred million stars. Credit: Dark Energy
Survey.
Tonight, as the sun sinks below the horizon, the world’s most powerful digital camera will once again turn its gleaming eye skyward. Tonight, and for hundreds of nights over the next five years, a team of physicists and astronomers from around the globe, working from an observatory in Chile, will use this remarkable machine to try to answer some of the most fundamental questions about our universe.
On Aug. 31, the Dark Energy Survey (DES) officially began. Scientists
on the survey team will systematically map one-eighth of the sky (5000
square degrees) in unprecedented detail. The start of the survey is the
culmination of ten years of planning, building, and testing by
scientists from 25 institutions in six countries.
The survey’s goal is to find out why the expansion of the universe is
speeding up, instead of slowing down due to gravity, and to probe the
mystery of dark energy, the force believed to be causing that
acceleration.
“The Dark Energy Survey will explore some of the
most important questions about our existence,” said James Siegrist,
Associate Director for High Energy Physics at the U.S. Department of
Energy’s Office of Science. “In five years’ time, we will be far closer
to the answers, and far richer in our knowledge of the universe.”
“With the start of the survey, the work of more
than 200 collaborators is coming to fruition,” said DES Director Josh
Frieman of the U.S. Department of Energy’s Fermi National Accelerator
Laboratory. “It’s an exciting time in cosmology, when we can use
observations of the distant universe to tell us about the fundamental
nature of matter, energy, space, and time.”
The main tool of the survey is the Dark Energy Camera, a
570-megapixel digital camera built at Fermilab in Batavia, Illinois, and
mounted on the 4-meter Victor M. Blanco telescope at the National
Science Foundation’s Cerro Tololo Inter-American Observatory in the
Andes Mountains in Chile. The camera includes 5 precisely shaped lenses,
the largest nearly a yard across, that together provide sharp images
over its entire field of view.
The Dark Energy Camera is the most powerful survey instrument of its
kind. With each snapshot, it will be able to see light from more than
100,000 galaxies up to 8 billion light years away.
“The start of the Dark Energy Survey is an
important milestone,” said CTIO Director Nicole van der Bliek.
“The Dark
Energy Camera, in conjunction with the Blanco telescope here at CTIO,
will greatly increase our understanding of the forces that control the
expansion of our universe.”
Over five years, the survey will obtain color images of 300 million
galaxies and 100,000 galaxy clusters and will discover 4,000 new
supernovae, many of which were formed when the universe was half its
current size. The data collected will be processed at the National
Center for Supercomputing Applications (NCSA) at the University of
Illinois in Urbana, and then delivered to collaboration scientists and
the public.
“NCSA is pleased to be producing and distributing
the refined data products that will enable this science,” said Don
Petravick, principal investigator of the DES Data Management Operation.
The survey’s observations will not be able to see dark energy
directly. However, by studying the expansion of the universe and the
growth of large-scale structure over time, the survey will give
scientists the most precise measurements to date of the properties of
dark energy.
“We’re looking at this big galaxy map of the
universe as a way of finding evidence for dark energy and characterizing
its nature with cosmic epoch,” said Ofer Lahav of University College
London and head of the DES Science Committee. “An even more challenging
goal for DES is to tell if what causes the acceleration of the universe
is indeed dark energy, or something entirely different.”
The survey will use four methods to probe dark energy:
- Counting galaxy clusters. While gravity pulls
mass together to form galaxies, dark energy pushes it apart. The Dark
Energy Camera will see light from 100,000 galaxy clusters billions of
light years away. Counting the number of galaxy clusters at different
points in time sheds light on this cosmic competition between gravity
and dark energy.
- Measuring supernovae. A supernova is a star that
explodes and becomes as bright as an entire galaxy of billions of
stars. By measuring how bright they appear on Earth, scientists can tell
how far away they are. This information can be used to determine how
fast the universe has been expanding since the star’s explosion. The
survey will discover 4000 of these supernovae, which exploded billions
of years ago in galaxies billions of light years away.
- Studying the bending of light. When light from
distant galaxies encounters dark matter in space, it bends around the
matter, causing those galaxies to appear distorted in telescope images.
The survey will measure the shapes of 200 million galaxies, revealing
the cosmic tug of war between gravity and dark energy in shaping the
lumps of dark matter throughout space.
- Using sound waves to create a large-scale map of expansion over time. When the universe was less than 400,000 years old, the interplay between matter and light set off a series of sound waves traveling at nearly two-thirds the speed of light. Those waves left an imprint on how galaxies are distributed throughout the universe. The survey will measure the positions in space of 300 million galaxies to find this imprint and use it to infer the history of cosmic expansion.
The Dark Energy Survey is supported by funding from the U.S.
Department of Energy Office of Science; the National Science Foundation;
funding agencies in the United Kingdom, Spain, Brazil, Germany and
Switzerland; and the participating institutions.
More information about the Dark Energy Survey, including the list of
participating institutions, is available at the project website: www.darkenergysurvey.org.
Released by Fermilab, the National Optical Astronomy Observatory
(NOAO) and the National Center for Supercomputing Applications on behalf
of the Dark Energy Survey collaboration. NOAO is operated by the
Association of Universities for Research in Astronomy (AURA), Inc. under
cooperative agreement with the National Science Foundation.
Fermilab is America’s premier national laboratory for particle
physics research. A U.S. Department of Energy Office of Science
laboratory, Fermilab is located near Chicago, Illinois, and operated
under contract by the Fermi Research Alliance, LLC. Visit Fermilab’s
website at www.fnal.gov and follow us on Twitter at @FermilabToday.
The DOE Office of Science is the single largest supporter of
basic research in the physical sciences in the United States, and is
working to address some of the most pressing challenges of our time. For
more information, please visit science.energy.gov.
Fermilab Media Contact:
Andre Salles
Fermilab Office of Communication
Office: 630-840-3351
Email: media@fnal.gov
Science Contact:
Josh Frieman
Dark Energy Survey Director
Fermilab scientist and
University of Chicago professor
Office: 630-840-2226
Cell: 847-274-0429
Email: frieman@fnal.gov
Andre Salles
Fermilab Office of Communication
Office: 630-840-3351
Email: media@fnal.gov
Science Contact:
Josh Frieman
Dark Energy Survey Director
Fermilab scientist and
University of Chicago professor
Office: 630-840-2226
Cell: 847-274-0429
Email: frieman@fnal.gov
Media Contact:
Dr. Stephen Pompea
Public Information Officer
National Optical Astronomy Observatory
950 N. Cherry Ave
Tucson AZ 85719 USA
E-mail: spompea@noao.edu
Phone: (520) 318-8285
Dr. Stephen Pompea
Public Information Officer
National Optical Astronomy Observatory
950 N. Cherry Ave
Tucson AZ 85719 USA
E-mail: spompea@noao.edu
Phone: (520) 318-8285
