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SUPERMASSIVE BLACK HOLES SRJC, Spring 2014-PHYS43 Thea Dumont Kyle Cubba They are a class of black holes They are formidably larger than regular black holes They are gigantic (100,000 X -- 1,000,000,000 X SOLAR MASS) They are a source of quasars They live in the center of galaxies WHAT ARE THEY? WOAH. THATS A LOT OF MASS! but how big are they? _ For their mass, they’re Schwarzschild radius (event horizon) is rather big. Dividing the mass by the volume defined by the Schwarzschild radius, the density of most supermassive black holes is less than that of water! Schwarzschild radius is the radius at which light itself cannot escape from the gravitational pull of the black hole. The surface this covers in three dimensional space surrounding a black hole is known as its event horizon. The true density of any black hole is unknown, since it is impossible to visually see what happens beyond the event horizon. General relativity describes that there is a gravitational singularity at the center of the black hole. But then again, general relativity says a lot of things that no one seems to know why. Hippies say that they are wormholes to extradimensional universes. black holes bend space-time A normal star only curves space-time by a small amount; But a black hole bends it to an asymptote. Black Holes & Light Bending Since black holes bend space-time, light bends around black holes Photon sphere supermassive black hole at the center of active galactic nucleus note the light bending occurring here More examples of light bending Proposed by Albert Einstein when coming up with general The “Einstein relativity. Ring” Happens when a bright object is directly behind massive object. SUPERMASSIVE BLACK HOLES & GALAXY FORMATION Supermassive black holes are found in active galactic nuclei (AGN). AGN is a compact center which emits high intensity light of many wavelengths ranging from radio to x-ray. Quasars are a class of AGN species; quasars have supermassive black holes at their center and are surrounded by accretion disks, relativistic jets spew from one or either poles orthogonal to the disk plane. Active galactic nucleus (AGN) Ejected matter The rotating speed of supermassive black holes and the rotating speed of the AGN are the same. This leads to the mature formation of galactic centers in host galaxies to supermassive black holes. The presence of a supermassive black hole influences the galaxy to take on a spheroidal shape (elliptical and spiral galaxies), as well as condenses the galaxy. Influences galaxies to merge creating a spiral. Galactic halo formation could also be explained by the presence of supermassive black holes. The supermassive black hole in the sombrero galaxy (shown above) is measured to be 1 billion times the mass of the sun, making it one of the largest known black holes! How do we know this? Black holes eject charged particles in jets as they accrete which we can spot. When we inspect the nucleus of galaxies, such as m87, and there are these jets, this implies there could be a supermassive black hole there. Stars in the AGN seem to be orbiting some unseen massive object, this could inferred to be a supermassive black hole. More material being ejected from a galactic center. Notice the accretion disk around the center. Supermassive Black Holes & Light Emission Supermassive black holes can be found because of the large amount of strong radio waves they emit because of the matter heating up in the accretion disk. As the matter enters the black hole, x-rays are produced; another way researchers have to detect supermassive black holes. Sagittarius A* in the Milky Way There is a supermassive black hole in the central bulge of the Milky Way, located it the Sagittarius constellation. The supermassive black hole is called Sagittarius A* or Sgr A* SGR A* - is 40 million times more massive than our own sun - has a radius of 6.7 light hours - was first discovered in 1973 because of its large amount of radio emissions - is orbited by multiple star systems Stars in orbit of Sagittarius A* Hurdling G2 Dust Cloud into Supermassive black hole at Galactic Center A dust cloud around 3 times the mass of the earth is hurdling at extremely high velocities towards Sgr A* Dust-Cloud Ripped Apart by Milky Way’s SMBH What would it be like to fall in one? Most likely very unpleasant. You’re probably cool Risky: one wrong move and you plunge into the heart of a black hole Done for: energy input is required to keep you from falling in No escape: be prepared to fall into an infinite abyss You collapse into nothing Spagettification In a normal black hole, tidal forces are strong and cause elongation (spagettification) because of the difference in gravitational potential between your feet and your head Visualizing the Gravitational Vector Field oh no! The bright side: at least you look trim In a supermassive black hole, however, the tidal forces are weaker since gravitational pull falls off at an inverse square; you would be within the event horizon before being pulled apart. You never see the singularity, as the light falls into it and never comes out. BYE-BYE UNIVERSE And hello Void! The light pouring in from the universe collapses into one bright point as you fall into the singularity and are obliterated from history, forever. PURELY THEORETICAL NO BASIS IN REALITY end Work Cited 1. Philip F. Hopkins et al. 2006 , “A Unified, Merger-driven Model of the Origin of Starbursts, Quasars, the Cosmic X-Ray Background, Supermassive Black Holes, and Galaxy Spheroids,” Philip F. Hopkins et al. 2006 ApJS 163 1. Web, accessed 12 May 2014. 1. Marta Volonteri et al. (2003), “The Assembly and Merging History of Supermassive Black Holes in Hierarchical Models of Galaxy Formation.” ApJ, 583-599. Web, accessed 12 May 2014. 1. Haehnelt, M. G. and Kauffmann, G. (2000), “The correlation between black hole mass and bulge velocity dispersion in hierarchical galaxy formation models.” Monthly Notices of Royal Astronomical Society. 318: L35-L38. Web, accessed 12 May 2014. 1. Jarrett L.Johnson et al. (2013), “Supermassive Seeds for Supermassive Black Holes.” The Astrophysical Journal, 771. Web, accessed 12 May 2014. 5. Ander Hamilton. http://jila.colorado.edu/~ajsh/insidebh/ Journey to the Schwarzschild Black Hole, 2014.Web, accessed 12 May14 6. http://csep10.phys.utk.edu/astr162/lect/active/smblack.html.
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