Simulations of Merging Galaxies 

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Dynamical modeling:   Collisional perturbation Self gravitating response Gas inflow + activity Merger (Noguchi 1987;  Barnes 1988; Barnes & Hernquist 1991, 1996; Mihos etal 1992, 1993; Mihos & Hernquist 1994, 1996; Hernquist & Mihos 1995; Bekki 1998; Gerritsen 1999)

Gaseous inflow and central activity are driven by gravitational torques:
(Noguchi 1987; Barnes & Hernquist 1991; Mihos & Hernquist 1996)
 

Gas Angular Momentum	Physical Torques	Gravitational Torques
	(from Mihos & Hernquist 1996)

 

From Mihos & Hernquist (1996)  Thumbnail physics: Isothermal Gas (10,000K) Schmidt law n=1.5 Kinetic Feedback (little effect) Inflows and starbursts can be altered by disk stability: Presence/absence of a central bulge (Mihos & Hernquist 1994, 1996)   Reduced disk surface density (eg, LSBs; Mihos, McGaugh, & de Blok 1997; Mihos 1999)   Suppressing orbital resonances (Barnes & Hernquist 1996)

How robust are these results?

Bekki (1998) Sticky Particles Schmidt law n=2 No feedback
Gerritsen and Icke (1999) Heating/Cooling Jeans Unstable Pressure Particle Feedback

Conclusions:

• Inflow mechanism and starburst timescales fairly robust, but absolute SFRs less so.
• Qualitative morphology (ie, disk vs nuclear) good, but details remain unresolved.