What forms AGN Jets? Magnetic fields are ferociously twisted in the disk.

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1 What forms AGN Jets? Magnetic fields are ferociously twisted in the disk. Charged particles are pulled out of the disk and accelerated like a sling-shot. Particles are bound to the magnetic fields, focussed into a beam!

2 31 Flavors Different type of AGN s may be only a matter of how the inner disk and jet are viewed. Unification model for active nuclei

3 The Dawn of the Universe

4 Question Why is the sky dark at night? Imagine looking through a forest of trees. The larger the forest, the fewer the gaps. Small Wood Large Forest

5 Olber s Paradox If the forest is large enough, there are no gaps. The universe is the same way. If the universe were infinitely large and old, every direction on the sky would land on the surface of a star somewhere.

6 Olber s Paradox If the forest is large enough, there are no gaps. The universe is the same way. If the universe were infinitely large and old, every direction on the sky would land on the surface of a star somewhere.

7 Olber s Paradox If the forest is large enough, there are no gaps. The universe is the same way. If the universe were infinitely large and old, every direction on the sky would land on the surface of a star somewhere.

8 Olber s Paradox If the universe were unchanging and infinite, the sky would be uniformly bright! The Big Bang solves this problem neatly: the universe has changed over time, and was once tiny. The observable universe we can therefore see is finite. Hence, the night sky is dark.

9 A Brief History of the Universe

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11 From initial seeds to the present day: Accumulation of matter through accretion and mergers. Joint evolution of stars and black holes. Rise of heavy elements and organic compounds.

12 The cosmological principle: The universe is isotropic and homogenous. We don t have a special point of view in the universe. The universe looks the same from all vantage points.

13 The Microwave Background Early universe was very hot. The free electrons trapped high energy photons in the hot plasma of the early universe. After 1 million years, the universe cooled enough so that electrons combined with H and He nuclei into Atoms: photons stream freely. Billions of years later, those photons have been stretched by the expanding universe into the microwave.

14 CMB The Cosmic Microwave Background is the redshifted perfect Blackbody remnant of the big bang! It is nearly uniform, but has tiny fluctuation in temperature that correspond to initial over and under-densities of matter.

15 Discovery 1965: Penzias and Wilson Studying microwave emission of the galaxy, but couldn t eliminate a hiss that filled the sky and never changed. Peaks at 1.06mm, Precisely 2.725K! A perfect blackbody!

16 Discovery 1965: Penzias and Wilson Studying microwave emission of the galaxy, but couldn t eliminate a hiss that filled the sky and never changed. Peaks at 1.06mm, Precisely 2.725K! A perfect blackbody!

17 CMB everywhere The CMB fills space, and is always streaming in. About 1% of the static on older analog TV s comes directly from the CMB.

18 The Big Bang We are Here

19 Variations: 10-5!

20 Planck: Even better map of the CMB

21 WMAP CMB studies: matter in universe is 16 baryonic, 84% non-baryonic dark matter. The mass equivalent energy density Dark Energy dominates the composition of the universe.

22 Evidence for the Big Bang Olber s paradox: The universe had a beginning! Universal expansion: Hubble s Law. Remnant heat of the big bang: the CMB has precisely the right temperature. The abundance of Hydrogen and Helium is precisely what is predicted by modeling the Big Bang.

23 Even Earlier At Times earlier than when the CMB was formed, the universe was increasingly denser and hotter. Eventually, known laws of physics are not able to explain the qualities of the universe! Now

24 Planck Era sec We have no physics to understand the Universe before sec. We need quantum gravity (string theory)?

25 GUT Era sec GUT: Grand Unified Theory Three of the four known forces of nature were combined!

26 Electroweak Era sec Electroweak forces separates into weak force and electromagnetic force. We have direct evidence that these forces unite into one.

27 Particle Era sec Temperature falls, matter and energy can no longer transform into each other. Left with protons, neutron, electrons, neutrinos (and maybe WIMPs). Matter outnumbered anti-matter. We don t know why.

28 Era of Nucleosynthesis sec 3 min Protons and neutrons combine to form Hydrogen and Helium. We are left with 75% H and 25% helium in the universe. No other baryonic matter.

29 Era of Nuclei 3 min 380,000 years H and He nuclei, electrons, and photons all move together. Just as in the sun s center, photons cannot move far before hitting an electron.

30 Era of Atoms 380,000 years 10 9 years At 3000K, H and Helium atoms are formed (electrons combine) Photons in the bath of matter and radiation now move freely. We see these very photons today as the Cosmic Microwave Background.

31 Era of Galaxies 10 9 years present Areas of slightly higher density in the Universe start the formation of galaxies, and galaxy clusters.

32 New Theories Primoridal dimensionality of the universe: Shortly after the big bang, did the universe have just one dimension?

33 Reminders/Assignments Still no outline from some of you: points are deducting! Online Assignment: George Smoot on the design of the universe Read: Ned Wright s Frequently Asked Questions in Cosmology