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Lecture 10: Black Holes and How They Shine Astronomy 5: The Formation and Evolution of the Universe Sandra M. Faber Spring Quarter 2007 UC Santa Cruz Photon paths around objects of same mass and increasing density. Baltimore seen through a strong gravitational lens QuickTime™ and a Cinepak decompressor are needed to see this picture. Approaching a black hole. R goes from 112RS down to 10 RS QuickTime™ and a YUV420 codec decompressor are needed to see this picture. Orbiting around a hole at 10 RS QuickTime™ and a YUV420 codec decompressor are needed to see this picture. We can use curved 2-d surfaces to model curved 3-d space The surfaces stand for the flat equatorial plane around a condensed object like a dense star or a black hole. Walking uphill (outwards) is analogous to moving radially outward from the dense object. Note that you walk a long way on the surface but the radius does not change very much. The usual formula of the circumference = 2R is wrong … the circumference is smaller than you expect. This is what we mean by “curved space.” Spacetime near a black hole Spacetime near a dense star Wormholes are mathematical solutions to GR that may not actually exist Wormhole connecting two universes Wormhole connecting two spots in the same universe. The centers of spheroids host massive black holes When gas falls onto The famous BHs,active they elliptical become active galactic M87 nuclei (AGN) and quasars (QSOs) Relativistic “jet” of ionized plasma 3 billion M central black hole Fly-in to the center of the M87 black hole QuickTime™ and a Sorenson Video 3 decompressor are needed to see this picture. Artist’s conception of accretion disk with jet QuickTime™ and a YUV420 codec decompressor are needed to see this picture. Feedback generated by stellar mergers (QSO mode) Sources of “feedback” during a merger: • Gas is funneled into the central regions, fueling a starburst and creating a wind (Mihos & Hernquist 1994). QSO phase • Orbital kinetic energy is converted to heat in cloud-cloud collisions, which drives a wind (Cox et al. 2005). • Gas driven to the center fuels a black hole, creating a quasar (QSO) whose feedback quenches further infall and star formation (Hopkins et al. 2005). Birth and death of a quasar during collision of two disk galaxies (gas only, stars not shown) QuickTime™ and a YUV420 codec decompressor are needed to see this picture.