arman khalatyan aip 2006
DESCRIPTION
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. - PowerPoint PPT PresentationTRANSCRIPT
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Arman KhalatyanAIP 2006GROUP meeting at AIP
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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
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The Scales.
A false color composite image of the central parsec of the GC taken by the Very LargeTelescope.Old, intermediate mass cool red giants and young massive hot blue stars.
Genzel et al. 2003
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Scales
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Galaxy Model• DM Halo-NFW profile• Disk – exponential
– stellar– gaseous
• Bulge – Hernquist profile
Springel et al. 2005
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Model-MULTIPHASE ISM, SFR
McKee & Ostriker (1977)McKee & Ostriker (1977)
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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
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SFR in MULTIPHASE ISM• Rates at which the masses of
the hot and cold phases evolve can be written:
• Effective EOS:
• Density dependence of the SN evaporation
• SFR:
Springel et al 2005
Note:we use q=0.05
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“GOLDEN RULE FOR SFR ?”• Kennicut law for sfr:
• SFR parameters:– t0
* 2.1 Gyr
– A0 1.0e4 K
– TSN 1.0e8 K
Springel et al 2005
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Cooling functionKatz et al. 1996
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Cooling function including metals
Dopita & Sutherland 2003
x95
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Modeling AGN• by Bondi(1952)
• 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
SPH implementation by Springel et al 2005
Energetic efficiency of black hole accretion 0.1
Hydrogen baryon fraction
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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
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Local M – T equilibrium • Black hole – IGM coupling factor:
Cattaneo 2006
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Parameter tests• Simulations was done by GAGDET-2 TreeSPH code.• Set of simulations was performed ( ~70 different mergers)
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Magorrian relation: MBH - Mbulge
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Parameter space study • Model parameters:
– physical: , , gas– numerical: MBH0, , NGB, qToomre
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Final BH mass vs and
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Mbh vs Mgas
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Suppression of SFR
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COOLING and BH-growth
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Gas temperature surrounding BH
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MOVIE
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Thank You for Your Attention.
To be continued…
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Next Step: CosmologyElliptical galaxy N198, Zoomed simulation in box 50Mpc/h with special resolution 1024^3 particlesMgas=5.9 1e5 M⊙
200 kpc/h
Z = 3.7