Binary Quasar Systems Gary Foreman

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Binary Quasar SystemsGary Foreman Prof. Marta
Volonteri

• Quasars General

• Powered by SMBHs in the center of galaxies
• Matter falling into the black hole converted into
  energy via E eMc2
• How do we ignite a quasar?

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Galactic Mergers start accretion
120 kpc
8 kpc
1 pc 3.26 ly 3.09 1018 cm
60 kpc
8 kpc
Galactic merger simulation from Mayer et al.
(2007)
160 pc
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Quasars Theory

• Assume All quasars are the offspring of
  galactic mergers?
• Assume All galaxies contain SMBHs that accrete
  sometime during merger?
• Black holes should stop accreting by the time the
  galactic merger is over (Hopkins et al. 2005)
• Quasars are observable for 107 yr?
  tEdd 0.14.5108 yr

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What is Eddington time (tEdd)?tEdd e 4.5108 yr

• tEdd quasar lifetime
• Time it takes for black hole mass to increase by
  a factor of e if the quasar is shining at LEdd
• LEdd is the maximum luminosity of the quasar
• Radiation pressure from accreting matter balances
  gravitational force on in falling gas
• Eddington ratio LBH / LEdd

Sir Arthur Stanley Eddington
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Quasars Observation

• 100,000 quasars have been observed
• 0.1 of observed quasars are binaries
• Why so few?

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Our Sample 95 Quasar PairsKochanek, Falco,
Muñoz (1999) Hennawi et al. (2006)Mortlock,
Webster, Francis (1999) Myers et al. (2006)

• Sloan measures
• g- and u-band magnitudes
• g-band 469 nm (blue/green light)
• u-band 355 nm (ultraviolet light)
• Redshifts (z)
• Angular separations (arcseconds)

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Our Calculations
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Results

• We find that our black hole masses are consistent
  with those reported in Warner, Hamann, and
  Dietrich (2003)
• Masses are on the high side

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Dynamical Friction Timescales
How long does it take for galactic components to
merge?

• Dark Matter Halos merge in 7 Myr
• Stellar Bulges merge in 110 Myr
• Black Holes merge in 24 Gyr

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Why is the Halo merging time so short?

• Halo merging time may be too short as many small
  quasar separations imply that halo merging is
  already underway

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Conclusions

• tEdd / tDF should equal 0.001
• However
• 107 / (7.0 106) 1.43
• 107 / (1.1 108) 0.09
• ???

• Quasar lifetime has been overestimated?
• Quasars obscured by the dust that powers them?
• Galactic mergers arent the only way to ignite
  quasars?
• Not all galaxies host a SMBH?