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5 Cards in this Set
- Front
- Back
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What are the consequences of galaxy collisions/interactions? |
1) One galaxy can strip away gas and dust from another galaxy. 2) Gravitational distortion of galaxies as they pass near each other. 3) Gas compression and the burst of star formation. 4) Galaxy mergers. 5) Triggering of the spiral density waves (spiral arms) in spiral galaxies. |
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What is the conclusion about the likelihood of collisions in rich/poor galaxy clusters? |
One would expect that the collisions between the galaxies are more frequent in the rich galaxy clusters than in the poor clusters. Such collisions would result in star formations, forcing the galaxy to use up its gas and dust. This is in agreement with the observation that ellipticals and Sa spirals are more common in the rich galaxy clusters. |
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What are superclusters? |
Clusters of galaxies form even bigger structures - the superclusters (clusters of clusters). The Local Group belongs to the Local Superclusters. They form filaments separated by voids. |
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What are active galaxies? |
A small percentage of galaxies are active galaxies - they emit a large amount of energy via radiation from the small volume in their nuclei (they are said to have Active Galactic Nuclei [AGN]). |
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What are Seyfert Galaxies? |
They are named after Carl Seyfert. They are spiral galaxies and the intensity of their radiation varies on time scale of minutes. From this we can conclude that the size of the active region responsible for radiation cannot be bigger than a few light-minutes (around 1 AU is smaller than the diameter of the galaxy). |
