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Episode
7: with guest Dr. Dale Frail from National Radio Astronomy Observatory |
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First detected in 1967 by satellites searching for the signatures of nuclear weapon detonations in space, gamma ray bursts, or GRBs, are extraordinarily luminous events visible in only the highest energy end of the electromagnetic spectrum. Since then, scientists have speculated about the origin of these distant and highly energetic events. Recent observations have provided enough information for astronomers to figure out what some of the GRBs are. |
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Listen (mp3, 11.3 MB) |
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Produced by the Astronomical Society of the Pacific
Written and narrated by Carolyn Collins Petersen
Original music by Geodesium
Soundtrack production by Loch Ness Productions
Web page materials by Andrew Fraknoi
Special thanks to Dr. Dale Frail and Dave Finley (NRAO)
Special thanks to Astrocast.TV, winner of 4 Telly Awards for 2010.
Gamma-Ray Bursts
A Collection of Resources to Get Behind the Headlines
Andrew
Fraknoi (Foothill College & ASP)
July 2010
First detected in 1967, gamma-ray bursts are very short, but extremely energetic òÀÜflashesòÀÝ seen in all directions around the sky. They were a major puzzle for astronomers in many ways -- why did they last so short a time; why did we almost never see two bursts in the same location; and, if they were really far away (as they turned out to be), what could explain the mind-boggling energy of these bursts?
The solution to the puzzle came when astronomers deployed satellites and networks to catch the òÀÜafterglowòÀÝ of the bursts -- the longer-lasting (and thus easier to study) radiation that followed the initial burst at lower energies, such as x-rays and even visible light. In the current decade, burst-hunting satellites such as Swift and Fermi have been providing new insights into the nature of these fascinating events, which are probably linked to such violent events as the deaths of the most massive stars or the collisions of star corpses.
This is a rapidly evolving field of astronomy, with new results coming at (pardon the pun) an explosive rate. So no popular book or article can be completely current; still, the resources below will guide you in your exploration of this field which is at the frontier of our knowledge of the some of the most destructive phenomena in the universe.
A. Introductory Material on Gamma-Ray Bursts
A1. Selected Non-technical Books
B. Specific Web Resources for Formal and Informal Educators
A. Introductory Material on Gamma-Ray Bursts
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Two neutron stars approach each other in a collision that will generate a gamma-ray burst. (Painting by Dana Berry, NASA) |
A1. Selected Non-technical Books
Katz, Jonathan The Biggest Bangs. 2002, Oxford U. Press. A book devoted to gamma-ray bursts, by a scientist in the field.
Schilling, Govert Flash: The Hunt for the Biggest Explosions in the Universe. 2002, Cambridge U. Press. Another book, this one by a leading science journalist.
Wheeler, J. Craig Cosmic Catastrophes: Exploding Stars, Black Holes, and Mapping the Universe, 2nd ed. 2007, Cambridge U. Press. This is a fine introduction to violent events in the universe by a noted astronomer, with a good section on gamma-ray bursts.
A2. Selected Non-technical Articles
Fox, D. & Racusin, J. òÀÜThe Brightest BurstòÀÝ in Sky & Telescope, Jan. 2009, p. 34. Nice summary of the brightest burst observed so far, and what we have learned from it.
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The afterglow of a gamma-ray burst detected from about 7.5 billion light years away using the Swift satellite. X-rays are seen on the left, ultra-violet waves on the right. (NASA Swift Team) |
Nadis, S. òÀÜDo Cosmic Flashes Reveal Secrets of the Infant Universe?òÀÝ in Astronomy, June 2008, p. 34. On different types of gamma-ray bursts and what we can learn from them.
Naeye, R. òÀÜDissecting the Bursts of DoomòÀÝ in Sky & Telescope, Aug. 2006, p. 30. Excellent review of gamma-ray bursts -- how we discovered them, what they might be, and what they can be used for in probing the universe.
Shilling, G. òÀÜStalking Cosmic ExplosionsòÀÝ in Astronomy, Feb. 2003, p. 48. Profile of Jan Van Paradijs and the hunt for what the bursts are.
Zimmerman, R. òÀÜWitness to Cosmic CollisionsòÀÝ in Astronomy, Jul. 2006, p. 44. On the Swift mission and what it is teaching astronomers about gamma-ray bursts.
Zimmerman, R. òÀÜSpeed MattersòÀÝ in Astronomy, May 2000, p. 36. On the quick-alert networks for finding afterglows.
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Artist’s Conception of the Swift Satellite observing a distance source with two beams of powerful gamma-rays. (Swift, NASA) |
A3. Selected Introductory Web Sites
Gamma-ray Bursts: Introduction to a Mystery (at NASAòÀÙs Imagine the Universe site):
http://imagine.gsfc.nasa.gov/docs/science/know_l1/bursts.html
Introduction from the Swift Satellite Site:
http://swift.sonoma.edu/about_swift/grbs.html
Brief Introduction by D. Perley (U. of California, Berkeley):
http://astro.berkeley.edu/research/grbs/grbinfo.html
Introduction for Serious Amateur Astronomers (from AAVSO):
http://www.aavso.org/observing/programs/hen/grb.shtml
The Discovery of Gamma-ray Bursts:
http://science.msfc.nasa.gov/science-news/science-at-nasa/1997/ast19sep97_2/
Some Missions to Detect and Learn More about Gamma-ray Bursts:
INTEGRAL Spacecraft: http://www.esa.int/science/integral
SWIFT Spacecraft: http://swift.sonoma.edu/
Fermi Space Telescope: http://fermi.gsfc.nasa.gov/public/
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A map of the sky around us showing the more than 2700 gamma-ray bursts observed by the Compton Gamma-ray Observatory satellite. Note that the dots representing the bursts are evenly distributed around the sky (and not in a flat disk, like our own Milky Way Galaxy). This observation that led astronomers to the conclusion that the burst must be located in distant galaxies around the universe, and not part of our home galaxy. (NASA) |
B. Specific Web Resources for Formal and Informal Educators
Classroom Materials from the Swift Satellite Education Group:
http://swift.sonoma.edu/education/index.html
Swift Eyes through Time is a unit developed at Pennsylvania State University, using gamma-ray bursts as the òÀÜhookòÀÝ to get middle-school students thinking about telescopes and astronomical observations in general:
http://www.wpsu.org/swift/index.html
A set of informational guides and activities about gamma-ray bursts developed at NASAòÀÙs Goddard Space Flight Center in 1999-2000 can be found at:
http://imagine.gsfc.nasa.gov/docs/teachers/gammaraybursts/
imagine/imagine_cover.html
OR
http://cmase.uark.edu/teacher/workshops/GEMS-lessons/Gamma%20Ray%20Bursts%209-12.pdf (This is now a bit dated, but some of the ideas in the booklet are still quite useful.)
Fermi Space Telescope materials for teachers:
http://glast.sonoma.edu/teachers/index.php#online