NASA Satellite, Controlled by Penn State, Detects Most Distant Explosion

Shows the counting rate in the gamma-ray instrument on Swift for two gamma-ray bursts. The top panel is for the high redshift burst observed on September 4, 2005 (GRB 050904). The bottom panel shows a typical burst for comparison; it is the one Swift detected on March 26, 2005 (GRB 050326). GRB 050904 is fainter and much longer than typical. Image credit: Dr. Neil Gehrels

NASA is announcing today the detection of the most distant explosion ever discovered, a gamma-ray burst from the edge of the visible universe. Penn State controls the science and flight operations of the satellite that detected the burst, NASA's Swift observatory, from the Mission Operations Center in University Park.

This powerful burst likely marks the death of a massive star and the birth of a black hole. Its signal reached Earth on 4 September, after traveling about 13 billion light years from an era soon after stars and galaxies first formed--about 500 million to 1 billion years after the Big Bang when the universe was only 5 percent as old as it is now.

"This discovery is a Penn State double whammy because it was detected first from space by the powerful Swift satellite and then observed from the ground by the Palomar sixty-inch telescope, in efforts led by Penn State astrophysicists John Nousek, David Burrows, and Derek Fox," says Peter Mészáros, Holder of the Eberly Family Chair in Astronomy and Astrophysics and leader of the Swift science team. "We've been waiting for nine months since Swift was launched to detect a really distant "high redshift" burst, and now we've finally got one," says David Burrows of Penn State, the lead scientist for Swift's X-ray telescope, one of three telescopes on the Swift observatory.

"This explosion is so far away that it is not visible in optical light, but we discovered that it is still quite bright in infrared light and X-rays," Derek Fox, assistant professor of astronomy and astrophysics at Penn State, who uses his computer to control the sixty-inch telescope at the Palomar Observatory in California. Another crucial set of observations were obtained on a Chilean telescope by Daniel Reichart, an astronomer at the University of North Carolina, who received undergraduate degrees from Penn State in 1996.

Stars shine by burning hydrogen. The process is called nuclear fusion. Hydrogen burning produces helium "ash." As the star runs out of hydrogen (and nears the end of its life), it begins burning helium. The ashes of helium burning, such as carbon and oxygen, also get burned. The end result of this fusion is iron. Iron cannot be used for nuclear fuel. Without fuel, the star no longer has the energy to support its weight. The core collapses. If the star is massive enough, the core will collapse into a black hole. The black hole quickly forms jets; and shock waves reverberating through the star ultimately blow apart the outer shells. Gamma-ray bursts are the beacons of star death and black hole birth. Image Credit: Nicolle Rager Fuller/NSF

"With out Swift, this burst never would have been detected," says John Nousek, professor of astronomy and astrophysics at Penn State and director of the Swift Mission Operations Center. The Swift observatory and the Swift Operation Center's procedures for sharing detection data are designed for unprecedented rapid response. Moments after Swift detected the gamma-ray burst, the Swift team rapidly alerted astronomers worldwide about the explosion so that major ground-based telescopes, including the Palomar Observatory, could focus on its fading embers in order to measure its astounding distance from Earth. "Combined data from the Swift satellite and ground based telescopes bagged the most distant gamma-ray burst ever observed, much farther way than any supernova and close to being the most distant object yet detected in the universe," Meszaros says.

"Soon, we expect that Swift will find bursts that are even farther back in time than this explosion--more distant than any object ever observed," says Burrows. "We are in the process of pushing back the boundaries of the observable universe."

NASA PRESS RELEASE:

A NASA press release concerning this discovery is pasted below.

ADDITIONAL IMAGES AND MORE INFORMATION:

http://www.nasa.gov/vision/universe/starsgalaxies/2005_distant_grb.html

CONTACTS AT NASA:

Dolores Beasley/Erica Hupp, NASA Headquarters,

dbeasley@nasa.gov / erica.hupp-1@nasa.gov, ( 202) 358-1753 / 1237

SCIENCE CONTACTS AT PENN STATE:

Derek Fox, assistant professor of astronomy and astrophysics: 814-863-4989,  dfox@astro.psu.edu

Peter Mészáros, head of the Swift science team and Holder of the Eberly Family Chair in Astronomy and Astrophysics: 814-865-0418, pmeszaros@astro.psu.edu

John Nousek, director of the Swift Mission Operations Center and professor of astronomy and astrophysics: 814-863-1937,  nousek@astro.psu.edu

P.I.O. CONTACTS:

Barbara K. Kennedy (Penn State PIO): 814-863-4682, science@psu.edu

Lynn Cominsky (Swift PIO): 707-664-2655, lynnc@universe.sonoma.edu

MORE INFORMATION ABOUT SWIFT:

http://swift.nasa.gov

http://swift.sonoma.edu/

http://www.science.psu.edu/alert/Swift.htm

THE FOLLOWING RELEASE IS FROM NASA HEADQUARTERS

Dolores Beasley, Headquarters, Washington (Phone: 202/358-1753)

Susan Hendrix, Goddard Space Flight Center, Greenbelt, Md. (Phone: 301/286-7745)

September 12, 2005, RELEASE: 05-259

Most Distant Explosion Detected, Smashes Previous Record

Scientists using NASA's Swift satellite and several ground-based telescopes have detected the most distant explosion yet, a gamma-ray burst from the edge of the visible universe.

This powerful burst was detected September 4. It marks the death of a massive star and the birth of a black hole. It comes from an era soon after stars and galaxies first formed, about 500 million to 1 billion years after the Big Bang.

"We designed Swift to look for faint bursts coming from the edge of the Universe," said Swift principal investigator Dr. Neil Gehrels of NASA Goddard Space Flight Center in Greenbelt, Md. "Now we've got one and it's fascinating. For the first time we can learn about individual stars from near the beginning of time. There are surely many more out there," he added.

Only one quasar has been discovered at a greater distance. Quasars are super-massive black holes containing the mass of billions of stars. This burst comes from a lone star. Scientists say it is puzzling how a single star could have generated so much energy as to be seen across the entire Universe. The science team has not yet determined the nature of the exploded star. A detailed analysis is forthcoming.

Scientists measure cosmic distances via redshift, the extent to which light is "shifted" toward the red, or lower energy, part of the electromagnetic spectrum during the light's long journey across the Universe. The greater the distance, the higher the redshift.

The September 4 burst, named GRB 050904, has a redshift of 6.29, which translates to a distance of about 13 billion light-years from Earth. The Universe is thought to be 13.7 billion years old. The previous most distant gamma-ray burst had a redshift of 4.5. The most distant quasar known is at a redshift of 6.4.

This burst was also very long, lasting more than 200 seconds, whereas most bursts last only about 10 seconds. The detection of this burst confirms that massive stars mingled with the oldest quasars. The detection also confirms that even more distant star explosions can be studied through combined observations of Swift and the network of world-class telescopes.

"This is uncharted territory," said Dr. Daniel Reichart, University of North Carolina (UNC), Chapel Hill, who spearheaded the distance measurement. "This burst smashes the old distance record by 500 million light-years. We are finally starting to see the remnants of some of the oldest objects in the Universe," he added.

Swift detected the burst and relayed its coordinates within minutes to scientists around the world. Reichart's team discovered the afterglow using the Southern Observatory for Astrophysical Research (SOAR) telescope atop Cerro Pachon, Chile. Over the net several nights, the UNC team used SOAR and the Gemini South telescope, also on Cerro Pachon, to calculate a redshift of greater than 6 using a light filtering technique. A team led by Nobuyuki Kawai of the Tokyo Institute of Technology used the Subaru Observatory on Mauna Kea, Hawaii, to confirm the distance and fine-tune the redshift measurement to 6.29, using a technique called spectroscopy.

"The earliest stars exploded eons ago, we know very little about them," said Josh Haislip, a UNC team member who analyzed data from SOAR. "One of the best ways we can study them is by watching for their explosions. Swift can pinpoint the location of the explosions, and telescopes such as SOAR can study the composition of the debris to understand where and when these stars formed and what they were made of," he added.

The SOAR telescope is funded by the U.S. National Optical Astronomy Observatory, Tucson, Ariz., through the National Science Foundation (NSF), Arlington, Va.; the Ministry of Science of Brazil; Michigan State University, East Lansing; and UNC. The twin Gemini Observatory telescopes represent an international partnership funded in part by the NSF. Goddard manages the Swift mission for NASA's Science Mission Directorate, Washington. Mission operations are conducted by Penn State University, University Park. Swift's other national laboratories, universities and international partners include the Los Alamos National Laboratory, N.M.; Sonoma State University, Rohnert Park, Calif.; the United Kingdom; and Italy.

For more information on the Internet, visit:

http://www.nasa.gov/vision/universe/starsgalaxies/2005_distant_grb.html

For more information about NASA and agency programs on the Internet, visit: http://www.nasa.gov/home

Nearly 13 billion years ago, an early massive star explodes. The light from the explosion, called a gamma-ray burst, traverses the Universe. On September 4, 2005, the NASA Swift satellite detects the burst and notifies scientists of its location. Scientists using the Southern Observatory for Astrophysical Research (SOAR) telescope atop Cerro Pachon, Chile, discover the burst afterglow and, with the help of other telescopes and science teams, nail down the distance. At redshift 6.29, the burst is by far the most distant known. Credit: Trent Schindler/NSF

Scientists Watch Baby Black Hole Get to Work Fast

This animation depicts what happens to the most massive stars when they die. When a massive star runs out of fuel, it no longer has the energy to support its mass. The core collapses and forms a black hole. Shockwaves bounce out and obliterate the outer shells of the star. Previously scientists thought that a single explosion is followed by a graceful afterglow of the dying embers. Now, according to Swift observations, it appears that a newborn black hole in the core somehow re-energizes the explosion again and again, creating multiple bursts all within a few minutes.