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2003

2003. Birth and Dynamics of Galactic Black Holes. Demography of quiescent black holes in the present-day universe Demography of accreting black holes (quasars) at early cosmic times Dynamics of black holes in galactic centers: Brownian motion, binaries

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2003

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  1. 2003

  2. Birth and Dynamics of Galactic Black Holes • Demography of quiescent black holes in the present-day universe • Demography of accreting black holes (quasars) at early cosmic times • Dynamics of black holes in galactic centers: Brownian motion, binaries • Effects of quasars on their cosmic habitat Collaborators: Rennan Barkana, Volker Bromm, Pinaki Chatterjee, . . Lars Hernquist, Stuart Wyithe

  3. The Black Hole in the Galactic Center: SgrA* VLT with Adaptive Optics • “3-color”: 1.5 - 3 um • 8.2 m VLT telescope • CONICA (IR camera) • NAOS (adaptive optics) • 60 mas resolution

  4. Stellar Positions & Motions Reid et al. 2002

  5. SgrA* in July 1995

  6. Where was Sgr A* in May‘02? • Sgr A* position: 10 mas • Star “S2” • seen at pericenter • V ~ 5000 km/s ! • Orbit determined

  7. S2’s orbit • 15 year period • e = 0.87 • Pericenter • 15 mas = 120 AU . = 17 light-hours (Schoedel et al 2002)

  8. Ghez et al. 2003 SO-16 closest approach at 90 AU Simultaneous fit of orbits implies: 1. BH mass: 2. BH proper motion: < 0.8+-0.7 mas/yr

  9. Feeding SgrA* with Stellar Winds Emission region: Loeb, astro-ph/0311512

  10. Sgr A*’s motion • Continues along Galactic Plane • Remove Sun’s motion • V(Sgr A*) < 7 km/s Reid et al. (2002)

  11. Lower Limit on Sgr A*’s Mass • Backer & Sramek (1999): MV2 ~ mv2 <energy> • Reid et al (1999): MV ~ mv <momentum> • Chatterjee, Hernquist & Loeb (2002) mass estimator: a <energy> Mlim ~ G M(R) m / R V2 • V < 2 km/s a M > 106 Msun

  12. Apparent Deviations from Keplerian Orbits Doppler transformation of time: BH star Loeb 2003 (astro-ph/0309716)

  13. Probing the Spacetime Around SgrA* with Pulsars ~10-100 massive stars with P<100 yr and lifetime of ~ ~1000 NS in steady state 1-10 detectable pulsars at 10-20 GHz • BH spin vector from frame-dragging + imaging of pulsar orbit • Inner stellar cluster from gravitational scattering events • Test accretion flow models by measuring plasma density Pfahl & Loeb 2003 (astro-ph/0309744)

  14. Enclosed Mass Schoedel et al. 2002

  15. Water Masers: NGC 4258 Moran, Greenhill, & Herrnstein (2000)

  16. Keplerian Velocity Profile Miyoshi et al. 1995

  17. Mass densities Object Density Method (Msun/pc3) M 87 2 x 106 HST: 3x109 Msun in 7 pc NGC 4258 7 x 109 VLBA : H2O3x107 Msun in 0.1 pc Sgr A* 8 x 1015 S16’s orbit 3x106 Msun in 90 AU Sgr A* 2 x 1021 Sgr A*s p.m. 1x106 Msun in 1 AU SMBH 5 x 1025 Rsch3x106 Msun in 0.05 AU

  18. Correlation between black hole mass and velocity dispersion of host stellar system Tremaine et al. 2002 Ferrarese 2002

  19. Quasars Reside in Galaxies

  20. Archeology of the Universe redshift distance Earth The more distant a source is, the more time it takes for its light to reach us. Hence the light must have been emitted when the universe was younger. By looking at distant sources we can trace the history of the universe.

  21. Quasars already exist at z~6, only a billion years after the big bang! Becker et al. 2001

  22. The Earliest Quasar Detected: z=6.43 Fan et al. 2002

  23. Cosmological Infall Around Quasars at z>6 Barkana & Loeb, Nature, 2003

  24. PhotoE time Lya Line of Quasars SDSS (Vanden Berk et al. 2001) Quasar spectrum HST (Telfer et al. 2002) ROSAT (Yuan et al. 1998) Ferrarese et al. 2002 Tremaine et al. 2002 Wyithe & Loeb 2002

  25. Basic Facts About the Universe HOMOGENEOUS: the same everywhere HOMOGENEOUS • On large scales our universe is simple: Observer 1 Observer 3 Observer 2 ISOTROPIC: the same in all directions Direction1 Direction 2 Earth Direction 3

  26. But on small scales the universe is clumpy Early times Density perturbation Mean Density Intermediate times Late times Bound Object Void

  27. Formation of Massive Black Holes in the First Galaxies Add Bromm Low-spin systems: Eisenstein & Loeb 1995 Numerical simulations: Bromm & Loeb 2002

  28. Eddington Limit Gravitational force per proton: BH gas Radiation force per electron: accretion For a spherical geometry, the outward radiation force balances the inward gravitational force at the Eddington luminosity: Accretion of fuel is possible only if

  29. halo velocity dispersion dynamical time of galactic disk After translating this relation matches the observed correlation in nearby galaxies (Tremaine et al. 2002; Ferarrese & Merritt 2002) Self-regulation of Supermassive Black Hole Growth quasar galactic disk Silk &Rees 1998; Wyithe & Loeb 2003

  30. Simple physical model: *Each galaxy merger leads to a bright quasar phase during which the black hole grows to a mass and shines at the Eddington limit. The duration of this bright phase is proportional to the (smaller than unity) mass ratio in the merger. *Merger rate: based on the extended Press-Schechter model in a LCDM cosmology. Quasar Luminosity Function duty cycle ~10 Myr Wyithe & Loeb 2002

  31. Did the most massive galaxies form at z>6,only a billion years after the Big-Bang? Stars=collisionless fluid late accretion Core of CDM halos stabilizes at z~6 Loeb & Peebles 2002

  32. Proposal confirmed by N-body simulations Gao Liang & Simon White (2003) Loeb & Peebles 2002

  33. Brownian Motion of a Massive Black Hole in a Stellar System For a non-Maxwellian distribution function of stars the black hole is not in strict equipartition Chatterjee, Hernquist, & Loeb 2001 (ApJ, PRL)

  34. Black Hole Binaries due to Galaxy Mergers

  35. X-ray Image of a binary black hole system in NGC 6240 10kpc z=0.025 Komossa et al. 2002

  36. Dynamics of black hole binaries wandering R Figure1.ps Numerical experiment: 400,000 stars M/M*=0.25% Typical binaries coalesce in less than 10 Gyr due to wandering Chatterjee, Hernquist, & Loeb 2002

  37. Open issue: kick velocity

  38. Laser Interferometer Space Antenna

  39. Gravitational Wave Amplitude from a Black Hole Binary at z=1

  40. Gravitational Radiation from Coalescence of Massive Black Hole Binaries PULSARS LISA REDSHIFT FREQUENCY (Hz) Wyithe & Loeb 2002

  41. Environmental Effects of Quasars Radiative:ionization of intergalactic hydrogen and helium Hydrodynamic:powerful relativistic outflows

  42. Spectrum of a High Redshift Quasar (z=5.73) Djorgovski et al. 2001, ApJL, submitted Transmitted flux ---> HI/HII<1e-6 (Fan et al. 2000)

  43. On the Threshold of the Reionization Epoch Djorgovski et al. 2001

  44. Structure Formation in the IGM Density contrast of gas at z=0 for a 100x100x10 Mpc^3 slice Density contrast of gas shocked between z=0.14-0.09

  45. Evolutionary Stages of Reionization neutral H • Pre-overlap • Overlap • Post-overlap Ionized H

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