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Gamma Ray Bursts (GRB)

Gamma Ray Bursts (GRB). Compton Gamma Ray Observatory (CGRO). Gamma Ray Bursts (GRB). Gamma Rays – the highest energy photons in the electromagnetic spectrum.

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Gamma Ray Bursts (GRB)

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  1. Gamma Ray Bursts (GRB) Compton Gamma Ray Observatory (CGRO)

  2. Gamma Ray Bursts (GRB) Gamma Rays – the highest energy photons in the electromagnetic spectrum Gamma-ray bursts - short-lived bursts of gamma ray photons, the most energetic form of light. At least some of them are associated with a special type of supernova, the explosions marking the deaths of especially massive stars.

  3. Gamma Ray Bursts (GRB) Lasting anywhere from a few milliseconds to several minutes, gamma-ray bursts shine hundreds of times brighter than a typical supernova and about a million trillion times as bright as the Sun, making them briefly the brightest source of cosmic gamma-ray photons in the observable universe. GRBs are detected roughly once per day from wholly random directions of the sky.

  4. Gamma Ray Bursts (GRB) No two gamma-ray bursts are the same, as can be seen from this sample of light curves.

  5. Gamma Ray Bursts (GRB) An Interesting Start Gamma Ray bursts were discovered serendipitously in the late 1960s by U.S. military satellites which were on the look out for Soviet nuclear testing in violation of the atmospheric nuclear test ban treaty. These satellites carried gamma ray detectors since a nuclear explosion produces gamma rays.

  6. Gamma Ray Bursts (GRB) As recently as the early 1990s, astronomers didn't even know if GRBs originated at the edge of our solar system, in our Milky Way Galaxy or incredibly far away near the edge of the observable Universe.

  7. Gamma Ray Bursts (GRB) Once discovered, GRBs were observed to be distributed uniformly over the sky. If they occurred within the galaxy, they should primarily occur in the Milky Way disk (where most of the stars in our galaxy are found). Either GRBs occurred outside of the galaxy or there is a “halo” around the Milky Way.

  8. Gamma Ray Bursts (GRB) If the GRBs were far away, they would have large Doppler shifts. However, with a Gamma Ray wavelength of on the order of 10-15, shifts are too small to measure Then…

  9. Gamma Ray Bursts (GRB) In 1997 the Dutch-Italian gamma-ray satellite Bepposax monitored a gamma-ray burst. Soon after, scientists could look with the Keck-telescope at the found spot. And thus the first spectrum of a fast-fading optical counterpart was obtained. The redshift of this spectrum places the gamma-ray burst at a distance of a few Gigaparsecs. This is in galaxies far, far away….

  10. Gamma Ray Bursts (GRB) The first optical images, taken with the Herschel-telescope, of the gamma-ray burst that was discovered at february 28 of 1997. At the top picture one can see the gamma-ray burst. At the bottom picture, taken eight days later, one can see the burst is fading away. (Gamma-ray bursts; G.J.Fishman D.H.Hartmann; Scientific American; March 1998)

  11. Gamma Ray Bursts (GRB) Long or Short Duration? Gamma Ray Bursts are separated into two classes: long-duration bursts and short-duration bursts. Long duration bursts – Gamma Ray Bursts that last more than 2 seconds. Short-duration bursts – Gamma Ray Bursts that last less than 2 seconds. Short duration bursts range from a few milliseconds to 2 seconds with an average duration time of about 0.3 seconds (300 milliseconds). The long-duration bursts last anywhere from 2 seconds to a few hundreds of seconds (several minutes) with an average duration time of about 30 seconds. Astronomers think that long and short duration GRBs are created by fundamentally different physical properties. And whereas they now are fairly confident of what drives the long GRBs, there are only theories when it comes to what drives short-duration bursts.

  12. Gamma Ray Bursts (GRB) Model for Long Duration Bursts Collapsar Model – The core of a massive star rapidly collapses into a black hole. In doing so, a shock wave is created in the same way as in a supernova, but the amount of gravitational energy is very large near the event horizon. An especially violent supernova occurs, shedding high energy photons (gamma rays). Hypernova – the especially violent supernova associated with gamma bursts.

  13. Gamma Ray Bursts (GRB) Model for Short Duration Bursts Binary Neutron Star Model – Gamma bursts created by the collision and coalescence of two neutron stars. Energy in the form of gamma rays is created for relatively short time periods in the collision process.

  14. Gamma Ray Bursts (GRB) Swift GRB Mission Latest NASA mission launched in November 2004. It is studying GRBs with more sensitivity than other instruments.

  15. Gamma Ray Bursts Sprites – Curious (non astronomical gamma rays) Sprites are created during lightning storms on earth. The are vertical ejections from the atmosphere, and have been detected by satellites. Sprites are generators or gamma rays

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  17. Gamma Ray Bursts (GRB)

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