New Gamma-Ray Burst Smashes Cosmic Distance Record (w/Video)

Apr 28, 2009 by Francis Reddy
Gamma-ray bursts longer than two seconds are caused by the detonation of a massive star at the end of its life. Jets of particles and gamma radiation are emitted in opposite directions from the stellar core as the star collapses. This animation shows what a gamma-ray burst might look like up close. Credit: NASA/Swift/Cruz deWilde

( -- NASA's Swift satellite and an international team of astronomers have found a gamma-ray burst from a star that died when the universe was only 630 million years old, or less than five percent of its present age. The event, dubbed GRB 090423, is the most distant cosmic explosion ever seen.

"Swift was designed to catch these very distant bursts," said Swift lead scientist Neil Gehrels at NASA's Goddard Space Flight Center in Greenbelt, Md. "The incredible distance to this burst exceeded our greatest expectations -- it was a true blast from the past."

At 3:55 a.m. EDT on April 23, Swift detected a ten-second-long of modest brightness. It quickly pivoted to bring its ultraviolet/optical and X-ray telescopes to observe the burst location. Swift saw a fading X-ray afterglow but none in visible light.

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Gamma-ray bursts longer than two seconds are caused by the detonation of a massive star at the end of its life. Jets of particles and gamma radiation are emitted in opposite directions from the stellar core as the star collapses. This animation shows what a gamma-ray burst might look like up close. Credit: NASA/Swift/Cruz deWilde

"The burst most likely arose from the explosion of a massive star," said Derek Fox at Pennsylvania State University. "We're seeing the demise of a star -- and probably the birth of a black hole -- in one of the universe's earliest stellar generations."

Gamma-ray bursts are the universe's most luminous explosions. Most occur when massive stars run out of nuclear fuel. As their cores collapse into a black hole or neutron star, gas jets -- driven by processes not fully understood -- punch through the star and blast into space. There, they strike gas previously shed by the star and heat it, which generates short-lived afterglows in many wavelengths.

"The lack of visible light alone suggested this could be a very distant object," explained team member Edo Berger of Harvard University.

Beyond a certain distance, the expansion of the universe shifts all optical emission into longer infrared wavelengths. While a star's ultraviolet light could be similarly shifted into the visible region, ultraviolet-absorbing grows thicker at earlier times. "If you look far enough away, you can't see visible light from any object," he noted.

Within three hours of the burst, Nial Tanvir at the University of Leicester, U.K., and his colleagues reported detection of an infrared source at the Swift position using the United Kingdom Infrared Telescope on Mauna Kea, Hawaii. "Burst afterglows provide us with the most information about the exploded star and its environs," Tanvir said. "But because afterglows fade out so fast, we must target them quickly."

This image merges data from Swift's Ultraviolet/Optical (blue, green) and X-Ray (orange, red) telescopes. No visible light accompanied the burst, which hints at great distance. The image is 6.3 arcminutes wide. Credit: NASA/Swift/Stefan Immler

At the same time, Fox led an effort to obtain infrared images of the afterglow using the Gemini North Telescope on Mauna Kea. The source appeared in longer-wavelength images but was absent in an image taken at the shortest wavelength of 1 micron. This "drop out" corresponded to a distance of about 13 billion light-years.

As Fox spread the word about the record distance, telescopes around the world slewed toward GRB 090423 to observe the afterglow before it faded away.

At the Galileo National Telescope on La Palma in the Canary Islands, a team including Guido Chincarini at the University of Milan-Bicocca, Italy, determined that the afterglow's so-called redshift was 8.2. Tanvir's team, gathering nearly simultaneous observations using one of the European Southern Observatory's Very Large Telescopes on Cerro Paranal, Chile, arrived at the same number. The burst exploded 13.035 billion light-years away.


"It's an incredible find," Chincarini said. "What makes it even better is that a telescope named for Galileo made this measurement during the year in which we celebrate the 400th anniversary of Galileo's first astronomical use of the telescope."

A few hours later, Tanvir's team confirmed the distance using one of the European Very Large Telescopes on Cerro Paranal in Chile.

The previous record holder was a burst seen in September 2008. It showed a redshift of 6.7, which places it 190 million light-years closer than GRB 090423.

NASA's Goddard Space Flight Center manages Swift. It was built and is being operated in collaboration with Pennsylvania State University, the Los Alamos National Laboratory in New Mexico, and General Dynamics of Gilbert, Ariz., in the United States. 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.

Source: NASA/Goddard Space Flight Center

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3 / 5 (4) Apr 28, 2009
Which mass causes a star to burst after at most 630 million years?
I'm looking forward to observations of GRBs which don't fit anymore into the standard model.
Apr 28, 2009
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2.4 / 5 (5) Apr 28, 2009
You know a model is broken when the average person asks questions about the validity of the Big Bang timeline....(The Emperor has no clothes)
5 / 5 (2) Apr 29, 2009
It looks like JWST or Herschel may be needed to provide crucial spectra of the host galaxy, to deduce properties such as metallicity, kinematics, and star-formation rates in the galaxy that contained the observed GRB 090423. In the meantime Swift or other space observatories may detect even more distant GRBs by chance, again helping astrophysicists deduce local conditions in the early universe. As Edo Berger has stated 'This most distant one demonstrates for the first time that massive stars exist at those very high red shifts. This is something people have suspected for a long time, but there was no direct observational proof. So that is one of the cool results from this observation.' Very cool, indeed!
3.5 / 5 (2) Apr 29, 2009
@ brant: You state 'You know a model is broken when the average person asks questions about the validity of the Big Bang timeline...'. This makes no sense. Why would any serious scientist judge the validity of the Big Bang theory based on questions or opinions of 'the average person'? Should we also evaluate General Relativity, Quantum Chromodynamics, Newtonian Gravity, etc. based on the opinions of the average person? Is this how you think science is done, based on questions and misconceptions of average people with absolutely no in depth knowledge of the topic?
1 / 5 (2) Apr 29, 2009
@ yyz; What's wrong with my question about the mass of a star which blows up after at most 630 million years? Isn't it a legitimate question? Am I supposed to be a mere believer? Here, science is not done but science is presented to the public.
BTW I happen to know that there are real scientists whose questioning of the standard model certainly can't be dismissed as being based on "misconceptions". E.g. Paul J. Steinhardt and Neil Turok.
5 / 5 (1) Apr 29, 2009
Most GRBs don't fit the standard model for star evolution.
But I'm simply amazed by this burst, it's so far in space-time, it's unbelievable. Though my ultimate favorite is
GRB 080319B. It's stunning to imagine that if you watched at the right time on clear sky, you could actually see it! And the energy it emitted is simply amazing.
2 / 5 (4) Apr 30, 2009

I agree the questions raised by this report of a gamma-ray burst from a star that died when the universe was only 630 million years old.

What is the powerful and mysterious energy source of a dead star?

Something is obviously wrong. The answer - available to anyone who carefully studies precise space-age data on the Sun and nuclear rest masses of the 3,000 different types of atoms that comprise the entire visible universe:

1. A Big Bang did NOT fill the universe with Hydrogen, the most dispersed form of nuclear matter, at some imaginary time, t = 0.

2. Hydrogen is NOT the most abundant element in the Sun, ordinary stars, or the cosmos - although stellar surfaces are covered with Hydrogen and stellar surfaces release this neutron decay-product into interstellar space.

3. The Sun, ordinary stars, and the cosmos are powered by repulsive forces between neutrons in compact nuclear cores. Neutron emission from dense nuclear objects is followed by neutron decay to Hydrogen. The Hydrogen - that is released from the Sun via the solar wind - is smoke from the solar nuclear furnace, not its fuel.

4. Positive H ions from neutron decay are accelerated upward from the solar core by deep-seated magnetic fields. This neutron decay-product acts as the "carrier gas" that maintains mass fractionation inside the Sun.

5. Mass fractionation covers the surfaces of the Sun and other stars with the lightest of all elements - Hydrogen.

6. When solar magnetic fields fail to reach the surface, as during the Maunder minimum, mass fractionation decreases and the abundances of heavy elements and heavy isotopes of each element increase in the photosphere.

See: "The Sun is a plasma diffuser that sorts atoms by mass," Physics of Atomic Nuclei 69 (2006) pp. 1847-1856: and/or

"Composition of the solar interior: Information from isotope ratios," Proceedings of the SOHO/GONG Conference on Helioseismology, Big Bear Lake, CA, USA, European Space Agency SP-517 (editor: Huguette Lacoste, 2003) 345-348:

With kind regards,
Oliver K. Manuel

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