Arman Khalatyan AIP 2006

Arman KhalatyanAIP 2006GROUP 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.

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

Scales

Galaxy Model• DM Halo-NFW profile• Disk – exponential

– stellar– gaseous

• Bulge – Hernquist profile

Springel et al. 2005

Model-MULTIPHASE ISM, SFR

McKee & Ostriker (1977)McKee & Ostriker (1977)

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

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

“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

Cooling functionKatz et al. 1996

Cooling function including metals

Dopita & Sutherland 2003

x95

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

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

Local M – T equilibrium • Black hole – IGM coupling factor:

Cattaneo 2006

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

Magorrian relation: MBH - Mbulge

Parameter space study • Model parameters:

– physical: , , gas– numerical: MBH0, , NGB, qToomre

Final BH mass vs and

Mbh vs Mgas

Suppression of SFR

COOLING and BH-growth

Gas temperature surrounding BH

MOVIE

Thank You for Your Attention.

To be continued…

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