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									Formation of Supermassive Black Holes

                   ●   Elisabeth Schlender
                       May 21st 2007
                   ●   Physics 496
What Is A Super Massive Black Hole?

●   A black hole with a mass between 105-1010 Mo

●   Compared to stellar mass BH 1.5-15 Mo
●   Thought to be in all galaxies with a central bulge
●   Have a low average density
    Must have been forming before universe was 109
    year old
           Evidence For SMBHs
●   Observing velocities of-
    –   Gas clouds around galactic nuclei
    –   Stars in the Milky Way core
●   The mass needed to hold those objects in
    orbit at that velocity can be calculated
●   Based on the size and mass of these
    objects, we can conclude they must be
            What Do SMBHs Do?
●   Power Active Galaxies
    –   Galaxies which give off more light than the
        combined luminosity of their stars
    –   An active galaxy can have a luminosity 100
        times that of a nonactive galaxy
    –   Accretion of matter around BH gives off wide
        array of radiation- from gamma to radio waves
         Formation Theories
●   Galactic formation
●   Galactic mergers
    Black hole combination
            Galactic Formation
●   Self gravitating gas rich nuclei of forming galaxy
●   Core eventually collapses under gravity
●   A quasi-star with very low entropy is formed
●   This star eventually collapses forming a stellar
    mass BH
●   The accretion of the surrounding materials
    eventually forms a SMBH
Evidence for Galactic Formation
●   Strong correlation between SMBH mass and
    structure of the central bulge and bulge
●   Implies that there is a relationship between
    the formation of the bulge and the SMBH
             Galactic Mergers
●   Merger of 2 gas rich galaxies results in large
    amounts of gas in center of merged galaxy
●   The resulting gas rich core creates a SMBH
    much the same way one would form through
    galactic formation
           Black Hole Mergers
●   Evidence exists that show that there might be
    intermediate mass BH in M82
●   IMBHs form from the merger of massive
    stars in dense star clusters
●   The merger of IMBHs could form a SMBH
      Problems with BH Merger
●   Right now there only exists 1 IMBH
    candidate, M82
●   Supermassive Black Holes
●   Toshikazu Ebisuzaki et al, (2001) Missing Link Found? The "Runaway"
    Path to Supermassive Black Holes. The Astrophysical Journal, 562:L19-
    L22, 2001 November 20
●   Mitchell C. Begelman et al, (2006) Formation of supermassive black
    holes by direct collapse in pre-galactic haloes. Monthly Notices of the
    Royal Astronomical Society 370 (1), 289–298.
●   Supermassive black hole. <http://en.wikipedia.org/wiki/Supermassive_black_hole>
●   Peter Erwin et al, The Correlation Between Supermassive Black Hole
    Mass and the Structure of Ellipticals and Bulges. December

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