Active Galaxies and Quasars!

1. Active Galaxies and Quasars!

2. Types of Galaxies • Normal Galaxy and Active Galaxy • Normal Galaxy • Just a normal galaxy • Emits mostly visible radiation • Active Galaxy • Thousands of times brighter than Normal Galaxy • Emit different radiation; more energy, but it is less visible

3. Energy of an Active Galaxies • The energy of an active galaxy is determined by its core. • Non-thermal process. (Meaning the process is not related to temperature!) • The lifetime energy of an active galaxy can be compared to the total energy of a black hole.

4. Properties of Active Galaxies • High luminosity • Non-thermal radiation • Small, bright core • Jets or explosive appearance • Non-stellar emission features • Possible “super massive” black hole in center

5. Seyfert Galaxy • Classified as “in-between” • Possible evolutionary link • Seyfert Galaxies appear similar to normal ones, however their core is 10,000 times more luminous. • Core is called Galactic nucleus, this is where the radiation jets shoot out from • Most of core’s energy is “invisible” and infrared • Galaxy rotates very fast around its core, thus the creation of all the radiant energy. • Rapid changes in the amount of emitted energy, this shows that the source of energy must be very compact

6. Radio Galaxy • Most of energy released is in the in the radio portion of the electromagnetic spectrum • Two types of radio galaxies: lobe radio galaxy and core halo galaxy. • Lobe radio galaxy • Energy is released from giant regions called radio lobes, hardly any energy is emitted from the core. • Radio Lobes are roundish clouds of radiation; not visible. • Some lobes can be 10 times the size of the Milky Way; can emit 10 times the amount of energy

7. Core-Halo Radio Galaxy • Most of energy emitted is from a small central nucleus, 1 pc across. This is referred to as the core. • Energy also emitted from a halo around the core. • Core-halo galaxies can be up to 18mpc across; the output of radio energy is the equivilant to the Milky Way • A large jet of energy is ejected from the center of the galaxy

8. Quasars • Are believed to be extremely bright and extremely far away from earth. • Most distant object found in the Universe, closest 270 mpc. • Luminosity can range from 10 to 10,000 times the Milky Way. Some are so bright they can be seen at 12 billon light years. • Most of their energy is emitted in the infrared spectrum • Are about 1 kpc across • They posses much of the same characteristics as active galaxies. • Like active galaxies the energy is drawn from a small central core.

9. Quasars… again…..YAY • The small central core of Quasars is expected to be a “super massive” black hole. • All galaxies are expected to have these in the center. • Quasars also posses jets of matter. • These jets appear faint

10. Relating them all • Characteristics of Active Galaxies and Quasars • High luminosities • Energy emission is non-stellar • Energy is high variable; small core • Emit jets of energy • Rapid internal motion of the energy producing region.

11. Central engine of active galaxies • Energy requirements. • Energy cannot be described as combinations of things. • To much, to little space • Energy is gamma and X-ray • Energy Production • The energy is a result of extremely fast rotation caused the black hole. • This is the accretion disk • http://astro.estec.esa.nl/SA-general/Projects/Integral/black_hole_500.mpg

12. Energy emission • 10 to 20% of total mass energy is radiated away. • Particles enter a magnetic field an spin in there releasing energy into space. • This magnetic field become tangled and creates the radio lobes. • The radio lobes and jets serve as a conductor of energy so it can be taken from the core and released into space.

13. Active galaxy

14. Central core • Super massive Black hole • Have mass of around 100 billion suns • The theory is that all galaxies have super massive Black holes in their core. • The Gravitational force from the core creates an accretion disk and produces large amounts of non-visible energy.

15. GRAVITATIONAL LENSING! • The light of another galaxy is bent by the gravitational field of one in front of a galaxy or close to it. The bend in space in turn bends the light so it appears that there are twin galaxies around another separate galaxy.

17. Does the position of the galaxy in front of another affect the lensing that is taking place? • Yes it does. The position of the galaxy that is blocking the one behind it can change the way the light bends meaning there would be a more extreme bend on one side making the galaxy behind appear closer to the one blocking it and its twin look farther away.

18. Evolution of GalaxiesOne Theory……. • Beginning with the highly luminous quasars • Decreasing in violence through the radio and Seyfert galaxies and ending with normal spirals and ellipticals • The central black holes that powered the early activity are still there at later times; they simply run out of fuel as time goes on

19. Evolution of GalaxiesAnother Theory….. • A Merger and an Irregular Galaxy combine to form a Black Hole • This newly formed Black Hole combines with a Quasar to form a Super massive Black Hole. • Over time, the Black Hole loses its power and slowly deteriorates into a Seyfert Active Galaxy. • This Active Galaxy continues to lose power and eventually deteriorates into a Normal Spiral Galaxy

20. This is what its like WHEN WORLD COLLLIDEEE…Galaxy collision  • This is a series of pictures depicting what it may look like if The Milky Way and Andromeda were to collide and come into contact with each other. The images depict the stars as particles of constant brightness.