UNIVERSITY PARK – An international program to unveil the nature of Dark Energy, the mysterious force that is causing the expansion of the universe to accelerate, has been awarded a grant of $8 million from the National Science Foundation (NSF). The survey, the Hobby-Eberly Telescope Dark Energy Project (HETDEX), is led by the University of Texas at Austin and includes Penn State, Texas A&M University, and three institutions in Germany.
“I am delighted that the Hobby-Eberly Telescope, and in particular the HETDEX team, has been recognized by the National Science Foundation as one of the leaders in addressing one of the most fundamental scientific questions of our time,” said Daniel Larson, Chair of the Hobby-Eberly Telescope (HET) Board of Directors and the Verne M. Willaman Dean of Penn State’s Eberly College of Science.Â
It has been known for 70 years that the universe is expanding, but in 1998 astronomers made an astonishing discovery — the rate of expansion was not decreasing, as expected due to the gravitational attraction of matter, but was actually increasing. “The discovery of the accelerating universe required the existence of an unknown material, labeled Dark Energy, which appears to comprise approximately 70 percent of the universe,” said Lawrence Ramsey, Head of Penn State’s Department of Astronomy and Astrophysics.
HETDEX plans to map the expansion history of the universe using a specially designed instrument, VIRUS, mounted on the HET at McDonald Observatory. VIRUS consists of 150 copies of a single spectrograph design, and in a single observation can obtain 33,000 spectra. HETDEX’s primary goal is to create a three-dimensional map of one million star-forming galaxies at a distance of approximately 10 billion light years.
“Removing our ignorance about 70 percent of the universe’s makeup is a challenge that McDonald Observatory is delighted to assume,” said McDonald Observatory Director David Lambert. The Principle Investigator of HETDEX is Gary Hill, Chief Astronomer of the McDonald Observatory. Karl Gebhardt, the Herman and Joan Suit Professor of Astrophysics at the University of Texas, is the Project Scientist, and Darren Depoy, the Rachal-Mitchell-Heep Endowed Professor of Physics at Texas A&M, will oversee the assembly and testing of the VIRUS instrument.
The HETDEX project is expected to begin in January 2012 and to acquire observations over the next three years. While the survey has been designed to investigate the nature of Dark Energy, the wealth of data produced can address a number of important scientific issues. “The HETDEX observations, in addition to revealing key information about the expansion history of the universe, also will provide important insights into the formation of galaxies,” said Robin Ciardullo, professor of astronomy and astrophysics at Penn State and a member of the HETDEX science team. “We will be obtaining information from a time before our Sun was born. We believe that many of the objects HETDEX detects will evolve someday into galaxies similar to the Milky Way, so the experiment also will be providing a glimpse into our galaxy’s infancy.”
Penn State astronomers involved in HETDEX include Ciardullo, Ramsey, Senior Scientist Caryl Gronwall, and Distinguished Professor Donald Schneider.
Established in 1932, the McDonald Observatory near Fort Davis, Texas, hosts multiple telescopes undertaking a wide range of astronomical research under the darkest night skies of any professional observatory in the continental United States. The Hobby-Eberly Telescope at McDonald Observatory is a joint project of the University of Texas at Austin, Penn State University, Stanford University, Ludwig-Maximilians-Universität München, and Georg-August-Universität Göttingen.
High-resolution images associated with this research, plus videos and links to more information, are online at the McDonald Observatory: http://mcdonaldobservatory.org/news/releases/2010/1020.html and http://www.youtube.com/mcdonaldobservatory.
Barbara Kennedy, Penn State University
