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Spiral Galaxies

Spiral Galaxies. Elliptical Galaxies. Irregular Galaxies. Classification of Galaxies. Properties of Galaxies. Other galaxy types : Peculiar, Interacting, Ring, Starburst, Dwarf, Luminous Infrared, Active Nuclei, Damped Lyman-alpha. Stephan’s Quintet – Colliding galaxies.

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Spiral Galaxies

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  1. Spiral Galaxies

  2. Elliptical Galaxies

  3. Irregular Galaxies

  4. Classification of Galaxies

  5. Properties of Galaxies Other galaxy types : Peculiar, Interacting, Ring, Starburst, Dwarf, Luminous Infrared, Active Nuclei, Damped Lyman-alpha

  6. Stephan’s Quintet – Colliding galaxies

  7. The “Anntenae” Galaxies – a case study

  8. Ring Galaxies – the “splash” Head-on collisions can produce a “ripple” of star formation that expands outwards.

  9. Galactic Superwinds

  10. The Magellanic Clouds Southern Hemisphere only These are the nearest irregular galaxies. There are others even closer, being torn apart by our Galaxy (last discovery: 2003 in Canis Major). Large Magellanic Cloud Small Magellanic Cloud

  11. Our Immediate Galactic Neighborhood

  12. Members of the Local Group

  13. M31 vs Milky Way Before the Sun dies, we may collide and merge with the Andromeda Galaxy… (not quite sure yet about this)

  14. Collisional Aftermath

  15. And outward…

  16. Galaxy Clusters Virgo Notice the giant ellipticals at the centers of many clusters. These are an example of “galactic cannibalism”. Coma

  17. Galactic Cannibals – Central CD Ellipticals At the heart of rich clusters, galaxies pass through the center and are disrupted and collected.

  18. Making a CD galaxy

  19. The Core of M87 (at the center of Virgo)

  20. Giant Radio Lobes Many such jets are seen. If they last long enough, they can blast out of the galaxy for millions of light years: the largest single coherent objects in the universe.

  21. Seyfert Galaxies Some galaxies have unusually bright nuclei… Increasing exposure times….

  22. Quasars(Quasi-stellar Objects) Strange “stars” were found with spectral lines that turned out to be normal lines but at extremely high red Doppler shifts. The expansion of the Universe means that they must be VERY far away, yet they were not too faint. Star QSO Even Seyfert nuclei would not be bright enough. The energy output would have to be up to 100’s of times that from a whole normal galaxy, but the source was point-like.

  23. Host Galaxies of Quasars Finally, we were able to obtain deep images of quasars, and show that indeed they are extremely bright galactic nuclei. The only power source that is adequate is a supermassive black hole, eating up to several solar masses per year.

  24. Supermassive Black Holes Centaurus A You know the Milky Way has a 3 million solar mass BH at its center. Are they common? Bigger? Luminosities seem to require them. How could we prove the theory? A billion solar-mass black hole is still only the size of the solar system.

  25. Measuring the Monster’s Mass

  26. Images of Active Galaxy disks Recently, the theory of AGN has received spectacular visual confirmation from the Hubble Space Telescope.

  27. Unification of Active Galactic Nuclei Depending on what the viewing angle is, what we see can be rather different. This is now sorted out.

  28. into the Universe…

  29. Large Scale Structure On the largest scales (100 million ly) the Universe takes on a “foamy” appearance, with great filaments and walls of galaxies and clusters, surrounding great “voids” that are relatively empty.

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