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Arman Khalatyan AIP 2006

AGN formation by Merging Galaxies. Arman Khalatyan AIP 2006. GROUP meeting at AIP. Outline. What is AGN? Scales The model Multiphase ISM in SPH SFR BH model Self regulated accretion ?! Galaxy mergers Setup, resolution, numeric's … Results Prospects. The Scales.

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Arman Khalatyan AIP 2006

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  1. AGN formation by Merging Galaxies. Arman Khalatyan AIP 2006 GROUP meeting at AIP

  2. Outline • What is AGN? • Scales • The model • Multiphase ISM in SPH • SFR • BH model • Self regulated accretion ?! • Galaxy mergers • Setup, resolution, numeric's … • Results • Prospects

  3. The Scales. A false color composite image of the central parsec of the GC taken by the Very Large Telescope. Old, intermediate mass cool red giants and young massive hot blue stars. Genzel et al. 2003

  4. Scales

  5. Galaxy Model • DM Halo-NFW profile • Disk – exponential • stellar • gaseous • Bulge – Hernquist profile Springel et al. 2005

  6. Model-MULTIPHASE ISM, SFR McKee & Ostriker (1977)

  7. Model-MULTIPHASE ISM, SFR • First implementation of two phase ISM was by G.Yepes et al (1997) for Eulerian code. • Modified and extended ISM model were implemented using SPH formalism by Springel et al 2003. • radiative heating and cooling • cold clouds embedded in an ambient hot medium • star formation • feedback from SN( thermal feedback and cloud evaporation) • Galactic winds and outflows • Metal enrichment

  8. Rates at which the masses of the hot and cold phases evolve can be written: Effective EOS: Density dependence of the SN evaporation SFR: SFR in MULTIPHASE ISM Note:we use q=0.05 Springel et al 2005

  9. SFR parameters: • t0* 2.1 Gyr • A0 1.0e4 K • TSN 1.0e8 K “GOLDEN RULE FOR SFR ?” • Kennicut law for sfr: Springel et al 2005

  10. Cooling function Katz et al. 1996

  11. x95 Cooling function including metals Dopita & Sutherland 2003

  12. Energetic efficiency of black hole accretion 0.1 Hydrogen baryon fraction Modeling AGN • by Bondi(1952) SPH implementation by Springel et al 2005 • A fractionof the power generated by the accretion of matter onto the black hole heats the surrounding gas at a rate: • The Cooling rate per unit mass of heated gas is: Cattaneo 2006

  13. The BH model • The heating rate per unit mass of the gas depends on three parameters: • the accretion efficiency with respect to the Bondi rate :  • the fraction of the accretion power converted into heat:  • the mass Mgas on which the heat is distributed Cattaneo 2006, Springel et al. 2005

  14. Local M – T equilibrium • Black hole – IGM coupling factor: Cattaneo 2006

  15. Parameter tests • Simulations was done by GAGDET-2 TreeSPH code. • Set of simulations was performed ( ~70 different mergers)

  16. Magorrian relation: MBH - Mbulge William C. Keel

  17. Parameter space study • Model parameters: • physical: , , gas • numerical: MBH0, , NGB, qToomre

  18. Final BH mass vs and 

  19. Mbh vs Mgas

  20. Suppression of SFR

  21. COOLING and BH-growth

  22. Gas temperature surrounding BH

  23. MOVIE

  24. Thank You for Your Attention. To be continued…

  25. Next Step: Cosmology Elliptical galaxy N198, Zoomed simulation in box 50Mpc/h with special resolution 1024^3 particles Mgas=5.9 1e5 M⊙ Z = 3.7 200 kpc/h

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