Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

NASA's Swift finds most distant gamma-ray burst yet

30.05.2011
On April 29, 2009, a five-second-long burst of gamma rays from the constellation Canes Venatici triggered the Burst Alert Telescope on NASA's Swift satellite. As with most gamma-ray bursts, this one -- now designated GRB 090429B -- heralded the death of a star some 30 times the sun's mass and the likely birth of a new black hole.

"What's important about this event isn't so much the 'what' but the 'where,'" said Neil Gehrels, lead scientist for Swift at NASA's Goddard Space Flight Center in Greenbelt, Md. "GRB 090429B exploded at the cosmic frontier, among some of the earliest stars to form in our universe."

Because light moves at finite speed, looking farther into the universe means looking back in time. GRB 090429B gives astronomers a glimpse of the cosmos as it appeared some 520 million years after the universe began.

Now, after two years of painstaking analysis, astronomers studying the afterglow of the explosion say they're confident that the blast was the farthest explosion yet identified -- and at a distance of 13.14 billion light-years, a contender for the most distant object now known.

Swift's discoveries continue to push the cosmic frontier deeper back in time. A gamma-ray burst detected on Sept. 4, 2005, was shown to be 12.77 billion light-years away. Until the new study dethroned it, GRB 090423, which was detected just six days before the current record-holder, reigned with a distance of about 13.04 billion light-years.

Gamma-ray bursts are the universe's most luminous explosions, emitting more energy in a few seconds than our sun will during its energy-producing lifetime. Most occur when massive stars run out of nuclear fuel. When such a star runs out of fuel, its core collapses and likely forms a black hole surrounded by a dense hot disk of gas. Somehow, the black hole diverts part of the infalling matter into a pair of high-energy particle jets that tear through the collapsing star.

The jets move so fast -- upwards of 99.9 percent the speed of light -- that collisions within them produce gamma rays. When the jets breach the star's surface, a gamma-ray burst is born. The jet continues on, later striking gas beyond the star to produce afterglows.

"Catching these afterglows before they fade out is the key to determining distances for the bursts," Gehrels said. "Swift is designed to detect the bursts, rapidly locate them, and communicate the position to astronomers around the world." Once word gets out, the race is on to record as much information from the fading afterglow as possible.

In certain colors, the brightness of a distant object shows a characteristic drop caused by intervening gas clouds. The farther away the object is, the longer the wavelength where this sudden fade-out begins. Exploiting this effect gives astronomers a quick estimate of the blast's "redshift" -- a color shift toward the less energetic red end of the electromagnetic spectrum that indicates distance.

The Gemini-North Telescope in Hawaii captured optical and infrared images of GRB 090429B's quickly fading afterglow within about three hours of Swift's detection. "Gemini was the right telescope, in the right place, at the right time," said lead researcher Antonino Cucchiara at the University of California, Berkeley. "The data from Gemini was instrumental in allowing us to reach the conclusion that the object is likely the most distant GRB ever seen."

The team combined the Gemini images with wider-field images from the United Kingdom Infrared Telescope, which is also located on Mauna Kea in Hawaii, to narrow estimates of the object's redshift.

Announcing the finding at the American Astronomical Society meeting in Boston on Wednesday, May 25, the team reported a redshift of 9.4 for GRB 090429B. Other researchers have made claims for galaxies at comparable or even larger redshifts, with uncertain distance estimates, and the burst joins them as a candidate for the most distant object known.

Studies by NASA's Hubble Space Telescope and the Very Large Telescope in Chile were unable to locate any other object at the burst location once its afterglow had faded away, which means that the burst's host galaxy is so distant that it couldn't be seen with the best existing telescopes. "Because of this, and the information provided by the Swift satellite, our confidence is extremely high that this event happened very, very early in the history of our universe," Cucchiara said.

Swift, launched in November 2004, is managed by Goddard. It was built and is being operated in collaboration with Penn State University, University Park, Pa., the Los Alamos National Laboratory in New Mexico, and General Dynamics of Gilbert, Ariz., in the U.S. International collaborators include the University of Leicester and Mullard Space Sciences Laboratory in the United Kingdom, Brera Observatory and the Italian Space Agency in Italy, and additional partners in Germany and Japan.

Images: http://www.nasa.gov/mission_pages/swift/bursts/swift-20110527.html

Francis Reddy | EurekAlert!
Further information:
http://www.nasa.gov

More articles from Physics and Astronomy:

nachricht A 100-year-old physics problem has been solved at EPFL
23.06.2017 | Ecole Polytechnique Fédérale de Lausanne

nachricht Quantum thermometer or optical refrigerator?
23.06.2017 | National Institute of Standards and Technology (NIST)

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: Can we see monkeys from space? Emerging technologies to map biodiversity

An international team of scientists has proposed a new multi-disciplinary approach in which an array of new technologies will allow us to map biodiversity and the risks that wildlife is facing at the scale of whole landscapes. The findings are published in Nature Ecology and Evolution. This international research is led by the Kunming Institute of Zoology from China, University of East Anglia, University of Leicester and the Leibniz Institute for Zoo and Wildlife Research.

Using a combination of satellite and ground data, the team proposes that it is now possible to map biodiversity with an accuracy that has not been previously...

Im Focus: Climate satellite: Tracking methane with robust laser technology

Heatwaves in the Arctic, longer periods of vegetation in Europe, severe floods in West Africa – starting in 2021, scientists want to explore the emissions of the greenhouse gas methane with the German-French satellite MERLIN. This is made possible by a new robust laser system of the Fraunhofer Institute for Laser Technology ILT in Aachen, which achieves unprecedented measurement accuracy.

Methane is primarily the result of the decomposition of organic matter. The gas has a 25 times greater warming potential than carbon dioxide, but is not as...

Im Focus: How protons move through a fuel cell

Hydrogen is regarded as the energy source of the future: It is produced with solar power and can be used to generate heat and electricity in fuel cells. Empa researchers have now succeeded in decoding the movement of hydrogen ions in crystals – a key step towards more efficient energy conversion in the hydrogen industry of tomorrow.

As charge carriers, electrons and ions play the leading role in electrochemical energy storage devices and converters such as batteries and fuel cells. Proton...

Im Focus: A unique data centre for cosmological simulations

Scientists from the Excellence Cluster Universe at the Ludwig-Maximilians-Universität Munich have establised "Cosmowebportal", a unique data centre for cosmological simulations located at the Leibniz Supercomputing Centre (LRZ) of the Bavarian Academy of Sciences. The complete results of a series of large hydrodynamical cosmological simulations are available, with data volumes typically exceeding several hundred terabytes. Scientists worldwide can interactively explore these complex simulations via a web interface and directly access the results.

With current telescopes, scientists can observe our Universe’s galaxies and galaxy clusters and their distribution along an invisible cosmic web. From the...

Im Focus: Scientists develop molecular thermometer for contactless measurement using infrared light

Temperature measurements possible even on the smallest scale / Molecular ruby for use in material sciences, biology, and medicine

Chemists at Johannes Gutenberg University Mainz (JGU) in cooperation with researchers of the German Federal Institute for Materials Research and Testing (BAM)...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Plants are networkers

19.06.2017 | Event News

Digital Survival Training for Executives

13.06.2017 | Event News

Global Learning Council Summit 2017

13.06.2017 | Event News

 
Latest News

Quantum thermometer or optical refrigerator?

23.06.2017 | Physics and Astronomy

A 100-year-old physics problem has been solved at EPFL

23.06.2017 | Physics and Astronomy

Equipping form with function

23.06.2017 | Information Technology

VideoLinks
B2B-VideoLinks
More VideoLinks >>>