Fichier:437992main CenA optical gamma composite labeled.jpg
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English: "This is something we've never seen before in gamma rays," said Teddy Cheung, a Fermi team member at the Naval Research Laboratory in Washington. "Not only do we see the extended radio lobes, but their gamma-ray output is more than ten times greater than their radio output." If gamma-ray telescopes had matured before their radio counterparts, astronomers would have instead classified Cen A as a "gamma-ray galaxy." The gamma-ray output from Cen A's lobes exceeds their radio output by more than ten times. High-energy gamma rays detected by Fermi's Large Area Telescope are depicted as purple in this gamma ray/optical composite of the galaxy. Credit: NASA/DOE/Fermi LAT Collaboration, Capella Observatory. |
| Date | |
| Source | Fermi Maps an Active Galaxy's 'Smokestack Plumes', url=http://www.nasa.gov/mission_pages/GLAST/news/smokestack-plumes.html. |
| Auteur | NASA/DOE/Fermi LAT Collaboration, Capella Observatory. |
| Autorisation (Réutilisation de ce fichier) |
Images from NASA are usually free of copyright and are in the PUBLIC Domain. |
"When one of these photons collides with a super-fast particle in the radio lobes, the photon receives such an energy boost, it becomes a gamma ray," explained co-author Lukasz Stawarz at the Japan Aerospace Exploration Agency in Sagamihara, Japan.
Although it sounds more like billiards than astrophysics, this process, called inverse Compton scattering, is a common way of making cosmic gamma rays. For Cen A, an especially important aspect is the case where photons from the cosmic microwave background ricochet off of the highest-energy particles in the radio lobes.
In dozens of active galaxies, this process has been shown to produce X-rays. But the Cen A study marks the first case where astronomers have solid evidence that microwave photons can be kicked up to gamma-ray energies.
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| Date et heure | Vignette | Dimensions | Utilisateur | Commentaire | |
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| actuel | 3 mai 2011 à 02:25 | | 1 963 × 2 570 (2,52 Mio) | wikimediacommons>Marshallsumter | {{Information |Description ={{en|1="This is something we've never seen before in gamma rays," said Teddy Cheung, a Fermi team member at the Naval Research Laboratory in Washington. "Not only do we see the extended radio lobes, but their gamma-ray outpu |
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