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When Galaxies Collide. But first dwarf and special galaxies. Dwarf Galaxies. Dwarf Galaxies are very small Only a few billion stars! Most are elliptical… None are spiral. Dwarf Galaxy Leo A companion of the Milky-Way. Have central cores that give off abnormal amounts of energy.
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When GalaxiesCollide But first dwarf and special galaxies
Dwarf Galaxies Dwarf Galaxies are very small Only a few billion stars! Most are elliptical… None are spiral. Dwarf Galaxy Leo A companion of the Milky-Way
Have central cores that give off abnormal amounts of energy. About 10% of Galaxies are active There are three types Radio Seyfert (See-furt) Quasars All seem to be powered by super-massive black holes Active Galaxies
Radio Galaxies • Center gives off energy in the radio spectrum • Caused by electrons moving near the speed of light. • Electrons are shot out in two jets creating radio producing “radio lobes”
Seyfert Galaxies • An Area within less than a light year of the center gives off as much visible light as the rest of the galaxy • Core ejects clouds of gas at as much 10,000 km/sec ( about 3% of the speed of light!) • Some are also Radio Galaxies
Quasars • Short for quasi-stellar radio source • Give off as much as 1000 times the energy the Milky-Way does! • As much as 10 billion LY away, on the edge of the Universe…thus from the beginning of time! • Few details due to extreme distance • Send out jets of gas at seemingly faster than light speeds
When Galaxies Collide Individual stars almost never collide In Collisions Larger Galaxies are formed: • Disk galaxies (S0) merge with surrounding globular clusters • Disks collide to form both elliptical and spiral galaxies • Colliding spirals may lose integrity and become elliptical In about four billion years … The Milky Waywill collide with Andromeda!
We know this because: More distant(thus older) groups of galaxies have … • More and smaller galaxies in the same volume and • More Spirals