Gamma-Ray Bursts

Descriptive Essay # 103308

Astronomy > Cosmology
Astronomy > Physics
Physics > Astrophysics

Gamma-Ray Bursts

This paper defines and analyses gamma-ray bursts.

1,316 words () | 13 sources | MLA | 2006 United States

Paper Summary:

In this article, the writer notes that about once a day, somewhere in the universe a burst of gamma rays appears as if out of nowhere. It lasts a very short time, no more than a few seconds, and then disappears. The writer points out that during the event, the level of radiation from the gamma-ray bursts is so high that it overwhelms any other gamma rays coming from other cosmic sources. It has also been observed that most gamma-ray bursts have an afterglow in the x-ray, and sometimes even optical, wavelengths ranges. The writer maintains that the research into gamma-ray bursts will continue until their nature is finally understood. The writer concludes that while this research goes on, the accumulated information and the intermediate hypotheses are already helping astronomers and cosmologists to better understand the universe, particularly the time when it was just beginning to form.

Outline:
Definition and Description
Research Goals
History
Analysis
Future Research

From the Paper:

"Despite the inconsistent nature of these bursts, some patterns have been identified. One prominent distinction is between long and short bursts, those over 2 seconds and those less than that. Analysis of almost 2,000 gamma-ray bursts recorded by the BATSE device on the Compton Gamma-Ray Observatory between 1991 and 2000 showed that each falls into one of two groups: the short bursts have closely-spaced high-energy photons; the long bursts' photons appear to have lower energy and are more widely spaced.
"Another pattern that was discovered is related to the degrees of brightening and fading that the bursts exhibit over time in various channels of the measured energy spectra over the life of the burst. This analysis showed that different bursts release their gamma rays at different rates in different energy spectra When plotted, these variations manifested themselves as 5 distinct patterns: flat, crescent (or double-crescent), loop, lobe and island."

Sample of Sources Used:

Bonnell, J., A Brief History of the Discovery of Cosmic Gamma-Ray Bursts, NASA Goddard Space Flight Center, April 17 1995, http://antwrp.gsfc.nasa.gov/htmltest/jbonnell/www/grbhist.html.
Brainerd, J. J., BATSE Gamma-Ray Burst Sky Map, NASA National Space Science and Technology Center, April 28 1998, http://www.batse.msfc.nasa.gov/data/grb/skymap.
Britt, Robert R., Gamma Ray Bursts and Supernovae, Space.com, October 21 1999, http://www.space.com/scienceastronomy/astronomy/grb_supernova_991021.html.
Daunt, Steven, A Mystery: Gamma-Ray Bursts, University of Tennessee Dept. of Physics & Astronomy, http://csep10.phys.utk.edu/astr162/lect/cosmology/gammaray.html.
Dooling, Dave, The Mysterious Fingerprints Of Gamma-Ray Bursts, Science@NASA, January 8 1999, http://science.nasa.gov/newhome/headlines/ast08jan99_1.htm.